init

.gitignore

@@ -0,0 +1,3 @@
+__pycache__
+.vscode
+flagged

Pipfile

@@ -0,0 +1,14 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+evaluate = "*"
+tree-sitter = "==0.2.2"
+gradio = "*"
+
+[dev-packages]
+
+[requires]
+python_version = "3.8"

README.md

@@ -1,12 +1,48 @@
 ---
-title: Codebleu
-emoji: 🏃
-colorFrom: pink
-colorTo: yellow
+title: codebleu
+tags:
+- evaluate
+- metric
+description: "CodeBLEU"
 sdk: gradio
-sdk_version: 3.9
+sdk_version: 3.0.2
 app_file: app.py
 pinned: false
 ---
 
-Check out the configuration reference at https://huggingface.co/docs/hub/spaces-config-reference
+# Metric Card for CodeBLEU
+
+***Module Card Instructions:*** *Fill out the following subsections. Feel free to take a look at existing metric cards if you'd like examples.*
+
+## Metric Description
+*Give a brief overview of this metric, including what task(s) it is usually used for, if any.*
+
+## How to Use
+*Give general statement of how to use the metric*
+
+*Provide simplest possible example for using the metric*
+
+### Inputs
+*List all input arguments in the format below*
+- **input_field** *(type): Definition of input, with explanation if necessary. State any default value(s).*
+
+### Output Values
+
+*Explain what this metric outputs and provide an example of what the metric output looks like. Modules should return a dictionary with one or multiple key-value pairs, e.g. {"bleu" : 6.02}*
+
+*State the range of possible values that the metric's output can take, as well as what in that range is considered good. For example: "This metric can take on any value between 0 and 100, inclusive. Higher scores are better."*
+
+#### Values from Popular Papers
+*Give examples, preferrably with links to leaderboards or publications, to papers that have reported this metric, along with the values they have reported.*
+
+### Examples
+*Give code examples of the metric being used. Try to include examples that clear up any potential ambiguity left from the metric description above. If possible, provide a range of examples that show both typical and atypical results, as well as examples where a variety of input parameters are passed.*
+
+## Limitations and Bias
+*Note any known limitations or biases that the metric has, with links and references if possible.*
+
+## Citation
+*Cite the source where this metric was introduced.*
+
+## Further References
+*Add any useful further references.*

app.py

@@ -0,0 +1,20 @@
+import evaluate
+from evaluate.utils import launch_gradio_widget
+# import re 
+
+# match = re.match(
+#                 r"^from\s+(\.?)([^\s\.]+)(?:[^\s]*)\s+import\s+[^#\r\n]*(?:#\s+From:\s+)?([^\r\n]*)",
+#                 "from .bleu import bleu",
+#                 flags=re.MULTILINE,
+#             )
+# match = re.match(r"^import\s+(\.?)([^\s\.]+)[^#\r\n]*(?:#\s+From:\s+)?([^\r\n]*)", "import .bleu", flags=re.MULTILINE)
+
+# print(match)
+module = evaluate.load("dvitel/codebleu")
+launch_gradio_widget(module)
+# src = 'class AcidicSwampOoze(MinionCard):§    def __init__(self):§        super().__init__("Acidic Swamp Ooze", 2, CHARACTER_CLASS.ALL, CARD_RARITY.COMMON, battlecry=Battlecry(Destroy(), WeaponSelector(EnemyPlayer())))§§    def create_minion(self, player):§        return Minion(3, 2)§'
+# tgt = 'class AcidSwampOoze(MinionCard):§    def __init__(self):§        super().__init__("Acidic Swamp Ooze", 2, CHARACTER_CLASS.ALL, CARD_RARITY.COMMON, battlecry=Battlecry(Destroy(), WeaponSelector(EnemyPlayer())))§§    def create_minion(self, player):§        return Minion(3, 2)§'
+# src = src.replace("§","\n")
+# tgt = tgt.replace("§","\n")
+# res = module.compute(predictions = [tgt], references = [[src]])
+# print(res)

bleu.py

@@ -0,0 +1,590 @@
+# -*- coding: utf-8 -*-
+# Natural Language Toolkit: BLEU Score
+#
+# Copyright (C) 2001-2020 NLTK Project
+# Authors: Chin Yee Lee, Hengfeng Li, Ruxin Hou, Calvin Tanujaya Lim
+# Contributors: Björn Mattsson, Dmitrijs Milajevs, Liling Tan
+# URL: <http://nltk.org/>
+# For license information, see LICENSE.TXT
+
+"""BLEU score implementation."""
+
+import math
+import sys
+from fractions import Fraction
+import warnings
+from collections import Counter
+
+from .utils import ngrams
+import pdb
+
+
+def sentence_bleu(
+    references,
+    hypothesis,
+    weights=(0.25, 0.25, 0.25, 0.25),
+    smoothing_function=None,
+    auto_reweigh=False,
+):
+    """
+    Calculate BLEU score (Bilingual Evaluation Understudy) from
+    Papineni, Kishore, Salim Roukos, Todd Ward, and Wei-Jing Zhu. 2002.
+    "BLEU: a method for automatic evaluation of machine translation."
+    In Proceedings of ACL. http://www.aclweb.org/anthology/P02-1040.pdf
+    >>> hypothesis1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which',
+    ...               'ensures', 'that', 'the', 'military', 'always',
+    ...               'obeys', 'the', 'commands', 'of', 'the', 'party']
+    >>> hypothesis2 = ['It', 'is', 'to', 'insure', 'the', 'troops',
+    ...               'forever', 'hearing', 'the', 'activity', 'guidebook',
+    ...               'that', 'party', 'direct']
+    >>> reference1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
+    ...               'ensures', 'that', 'the', 'military', 'will', 'forever',
+    ...               'heed', 'Party', 'commands']
+    >>> reference2 = ['It', 'is', 'the', 'guiding', 'principle', 'which',
+    ...               'guarantees', 'the', 'military', 'forces', 'always',
+    ...               'being', 'under', 'the', 'command', 'of', 'the',
+    ...               'Party']
+    >>> reference3 = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
+    ...               'army', 'always', 'to', 'heed', 'the', 'directions',
+    ...               'of', 'the', 'party']
+    >>> sentence_bleu([reference1, reference2, reference3], hypothesis1) # doctest: +ELLIPSIS
+    0.5045...
+    If there is no ngrams overlap for any order of n-grams, BLEU returns the
+    value 0. This is because the precision for the order of n-grams without
+    overlap is 0, and the geometric mean in the final BLEU score computation
+    multiplies the 0 with the precision of other n-grams. This results in 0
+    (independently of the precision of the othe n-gram orders). The following
+    example has zero 3-gram and 4-gram overlaps:
+    >>> round(sentence_bleu([reference1, reference2, reference3], hypothesis2),4) # doctest: +ELLIPSIS
+    0.0
+    To avoid this harsh behaviour when no ngram overlaps are found a smoothing
+    function can be used.
+    >>> chencherry = SmoothingFunction()
+    >>> sentence_bleu([reference1, reference2, reference3], hypothesis2,
+    ...     smoothing_function=chencherry.method1) # doctest: +ELLIPSIS
+    0.0370...
+    The default BLEU calculates a score for up to 4-grams using uniform
+    weights (this is called BLEU-4). To evaluate your translations with
+    higher/lower order ngrams, use customized weights. E.g. when accounting
+    for up to 5-grams with uniform weights (this is called BLEU-5) use:
+    >>> weights = (1./5., 1./5., 1./5., 1./5., 1./5.)
+    >>> sentence_bleu([reference1, reference2, reference3], hypothesis1, weights) # doctest: +ELLIPSIS
+    0.3920...
+    :param references: reference sentences
+    :type references: list(list(str))
+    :param hypothesis: a hypothesis sentence
+    :type hypothesis: list(str)
+    :param weights: weights for unigrams, bigrams, trigrams and so on
+    :type weights: list(float)
+    :param smoothing_function:
+    :type smoothing_function: SmoothingFunction
+    :param auto_reweigh: Option to re-normalize the weights uniformly.
+    :type auto_reweigh: bool
+    :return: The sentence-level BLEU score.
+    :rtype: float
+    """
+    return corpus_bleu(
+        [references], [hypothesis], weights, smoothing_function, auto_reweigh
+    )
+
+
+def corpus_bleu(
+    list_of_references,
+    hypotheses,
+    weights=(0.25, 0.25, 0.25, 0.25),
+    smoothing_function=None,
+    auto_reweigh=False,
+):
+    """
+    Calculate a single corpus-level BLEU score (aka. system-level BLEU) for all
+    the hypotheses and their respective references.
+    Instead of averaging the sentence level BLEU scores (i.e. marco-average
+    precision), the original BLEU metric (Papineni et al. 2002) accounts for
+    the micro-average precision (i.e. summing the numerators and denominators
+    for each hypothesis-reference(s) pairs before the division).
+    >>> hyp1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which',
+    ...         'ensures', 'that', 'the', 'military', 'always',
+    ...         'obeys', 'the', 'commands', 'of', 'the', 'party']
+    >>> ref1a = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
+    ...          'ensures', 'that', 'the', 'military', 'will', 'forever',
+    ...          'heed', 'Party', 'commands']
+    >>> ref1b = ['It', 'is', 'the', 'guiding', 'principle', 'which',
+    ...          'guarantees', 'the', 'military', 'forces', 'always',
+    ...          'being', 'under', 'the', 'command', 'of', 'the', 'Party']
+    >>> ref1c = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
+    ...          'army', 'always', 'to', 'heed', 'the', 'directions',
+    ...          'of', 'the', 'party']
+    >>> hyp2 = ['he', 'read', 'the', 'book', 'because', 'he', 'was',
+    ...         'interested', 'in', 'world', 'history']
+    >>> ref2a = ['he', 'was', 'interested', 'in', 'world', 'history',
+    ...          'because', 'he', 'read', 'the', 'book']
+    >>> list_of_references = [[ref1a, ref1b, ref1c], [ref2a]]
+    >>> hypotheses = [hyp1, hyp2]
+    >>> corpus_bleu(list_of_references, hypotheses) # doctest: +ELLIPSIS
+    0.5920...
+    The example below show that corpus_bleu() is different from averaging
+    sentence_bleu() for hypotheses
+    >>> score1 = sentence_bleu([ref1a, ref1b, ref1c], hyp1)
+    >>> score2 = sentence_bleu([ref2a], hyp2)
+    >>> (score1 + score2) / 2 # doctest: +ELLIPSIS
+    0.6223...
+    :param list_of_references: a corpus of lists of reference sentences, w.r.t. hypotheses
+    :type list_of_references: list(list(list(str)))
+    :param hypotheses: a list of hypothesis sentences
+    :type hypotheses: list(list(str))
+    :param weights: weights for unigrams, bigrams, trigrams and so on
+    :type weights: list(float)
+    :param smoothing_function:
+    :type smoothing_function: SmoothingFunction
+    :param auto_reweigh: Option to re-normalize the weights uniformly.
+    :type auto_reweigh: bool
+    :return: The corpus-level BLEU score.
+    :rtype: float
+    """
+    # Before proceeding to compute BLEU, perform sanity checks.
+
+    p_numerators = Counter()  # Key = ngram order, and value = no. of ngram matches.
+    p_denominators = Counter()  # Key = ngram order, and value = no. of ngram in ref.
+    hyp_lengths, ref_lengths = 0, 0
+
+    assert len(list_of_references) == len(hypotheses), (
+        "The number of hypotheses and their reference(s) should be the " "same "
+    )
+
+    # Iterate through each hypothesis and their corresponding references.
+    for references, hypothesis in zip(list_of_references, hypotheses):
+        # For each order of ngram, calculate the numerator and
+        # denominator for the corpus-level modified precision.
+        for i, _ in enumerate(weights, start=1):
+            p_i = modified_precision(references, hypothesis, i)
+            p_numerators[i] += p_i.numerator
+            p_denominators[i] += p_i.denominator
+
+        # Calculate the hypothesis length and the closest reference length.
+        # Adds them to the corpus-level hypothesis and reference counts.
+        hyp_len = len(hypothesis)
+        hyp_lengths += hyp_len
+        ref_lengths += closest_ref_length(references, hyp_len)
+
+    # Calculate corpus-level brevity penalty.
+    bp = brevity_penalty(ref_lengths, hyp_lengths)
+
+    # Uniformly re-weighting based on maximum hypothesis lengths if largest
+    # order of n-grams < 4 and weights is set at default.
+    if auto_reweigh:
+        if hyp_lengths < 4 and weights == (0.25, 0.25, 0.25, 0.25):
+            weights = (1 / hyp_lengths,) * hyp_lengths
+
+    # Collects the various precision values for the different ngram orders.
+    p_n = [
+        Fraction(p_numerators[i], p_denominators[i], _normalize=False)
+        for i, _ in enumerate(weights, start=1)
+    ]
+
+    # Returns 0 if there's no matching n-grams
+    # We only need to check for p_numerators[1] == 0, since if there's
+    # no unigrams, there won't be any higher order ngrams.
+    if p_numerators[1] == 0:
+        return 0
+
+    # If there's no smoothing, set use method0 from SmoothinFunction class.
+    if not smoothing_function:
+        smoothing_function = SmoothingFunction().method1
+    # Smoothen the modified precision.
+    # Note: smoothing_function() may convert values into floats;
+    #       it tries to retain the Fraction object as much as the
+    #       smoothing method allows.
+    p_n = smoothing_function(
+        p_n, references=references, hypothesis=hypothesis, hyp_len=hyp_lengths
+    )
+    s = (w_i * math.log(p_i) for w_i, p_i in zip(weights, p_n))
+    s = bp * math.exp(math.fsum(s))
+    return s
+
+
+def modified_precision(references, hypothesis, n):
+    """
+    Calculate modified ngram precision.
+    The normal precision method may lead to some wrong translations with
+    high-precision, e.g., the translation, in which a word of reference
+    repeats several times, has very high precision.
+    This function only returns the Fraction object that contains the numerator
+    and denominator necessary to calculate the corpus-level precision.
+    To calculate the modified precision for a single pair of hypothesis and
+    references, cast the Fraction object into a float.
+    The famous "the the the ... " example shows that you can get BLEU precision
+    by duplicating high frequency words.
+        >>> reference1 = 'the cat is on the mat'.split()
+        >>> reference2 = 'there is a cat on the mat'.split()
+        >>> hypothesis1 = 'the the the the the the the'.split()
+        >>> references = [reference1, reference2]
+        >>> float(modified_precision(references, hypothesis1, n=1)) # doctest: +ELLIPSIS
+        0.2857...
+    In the modified n-gram precision, a reference word will be considered
+    exhausted after a matching hypothesis word is identified, e.g.
+        >>> reference1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
+        ...               'ensures', 'that', 'the', 'military', 'will',
+        ...               'forever', 'heed', 'Party', 'commands']
+        >>> reference2 = ['It', 'is', 'the', 'guiding', 'principle', 'which',
+        ...               'guarantees', 'the', 'military', 'forces', 'always',
+        ...               'being', 'under', 'the', 'command', 'of', 'the',
+        ...               'Party']
+        >>> reference3 = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
+        ...               'army', 'always', 'to', 'heed', 'the', 'directions',
+        ...               'of', 'the', 'party']
+        >>> hypothesis = 'of the'.split()
+        >>> references = [reference1, reference2, reference3]
+        >>> float(modified_precision(references, hypothesis, n=1))
+        1.0
+        >>> float(modified_precision(references, hypothesis, n=2))
+        1.0
+    An example of a normal machine translation hypothesis:
+        >>> hypothesis1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which',
+        ...               'ensures', 'that', 'the', 'military', 'always',
+        ...               'obeys', 'the', 'commands', 'of', 'the', 'party']
+        >>> hypothesis2 = ['It', 'is', 'to', 'insure', 'the', 'troops',
+        ...               'forever', 'hearing', 'the', 'activity', 'guidebook',
+        ...               'that', 'party', 'direct']
+        >>> reference1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
+        ...               'ensures', 'that', 'the', 'military', 'will',
+        ...               'forever', 'heed', 'Party', 'commands']
+        >>> reference2 = ['It', 'is', 'the', 'guiding', 'principle', 'which',
+        ...               'guarantees', 'the', 'military', 'forces', 'always',
+        ...               'being', 'under', 'the', 'command', 'of', 'the',
+        ...               'Party']
+        >>> reference3 = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
+        ...               'army', 'always', 'to', 'heed', 'the', 'directions',
+        ...               'of', 'the', 'party']
+        >>> references = [reference1, reference2, reference3]
+        >>> float(modified_precision(references, hypothesis1, n=1)) # doctest: +ELLIPSIS
+        0.9444...
+        >>> float(modified_precision(references, hypothesis2, n=1)) # doctest: +ELLIPSIS
+        0.5714...
+        >>> float(modified_precision(references, hypothesis1, n=2)) # doctest: +ELLIPSIS
+        0.5882352941176471
+        >>> float(modified_precision(references, hypothesis2, n=2)) # doctest: +ELLIPSIS
+        0.07692...
+    :param references: A list of reference translations.
+    :type references: list(list(str))
+    :param hypothesis: A hypothesis translation.
+    :type hypothesis: list(str)
+    :param n: The ngram order.
+    :type n: int
+    :return: BLEU's modified precision for the nth order ngram.
+    :rtype: Fraction
+    """
+    # Extracts all ngrams in hypothesis
+    # Set an empty Counter if hypothesis is empty.
+
+    counts = Counter(ngrams(hypothesis, n)) if len(hypothesis) >= n else Counter()
+    # Extract a union of references' counts.
+    # max_counts = reduce(or_, [Counter(ngrams(ref, n)) for ref in references])
+    max_counts = {}
+    for reference in references:
+        reference_counts = (
+            Counter(ngrams(reference, n)) if len(reference) >= n else Counter()
+        )
+        for ngram in counts:
+            max_counts[ngram] = max(max_counts.get(ngram, 0), reference_counts[ngram])
+
+    # Assigns the intersection between hypothesis and references' counts.
+    clipped_counts = {
+        ngram: min(count, max_counts[ngram]) for ngram, count in counts.items()
+    }
+
+    numerator = sum(clipped_counts.values())
+    # Ensures that denominator is minimum 1 to avoid ZeroDivisionError.
+    # Usually this happens when the ngram order is > len(reference).
+    denominator = max(1, sum(counts.values()))
+
+    return Fraction(numerator, denominator, _normalize=False)
+
+
+def closest_ref_length(references, hyp_len):
+    """
+    This function finds the reference that is the closest length to the
+    hypothesis. The closest reference length is referred to as *r* variable
+    from the brevity penalty formula in Papineni et. al. (2002)
+    :param references: A list of reference translations.
+    :type references: list(list(str))
+    :param hyp_len: The length of the hypothesis.
+    :type hyp_len: int
+    :return: The length of the reference that's closest to the hypothesis.
+    :rtype: int
+    """
+    ref_lens = (len(reference) for reference in references)
+    closest_ref_len = min(
+        ref_lens, key=lambda ref_len: (abs(ref_len - hyp_len), ref_len)
+    )
+    return closest_ref_len
+
+
+def brevity_penalty(closest_ref_len, hyp_len):
+    """
+    Calculate brevity penalty.
+    As the modified n-gram precision still has the problem from the short
+    length sentence, brevity penalty is used to modify the overall BLEU
+    score according to length.
+    An example from the paper. There are three references with length 12, 15
+    and 17. And a concise hypothesis of the length 12. The brevity penalty is 1.
+        >>> reference1 = list('aaaaaaaaaaaa')      # i.e. ['a'] * 12
+        >>> reference2 = list('aaaaaaaaaaaaaaa')   # i.e. ['a'] * 15
+        >>> reference3 = list('aaaaaaaaaaaaaaaaa') # i.e. ['a'] * 17
+        >>> hypothesis = list('aaaaaaaaaaaa')      # i.e. ['a'] * 12
+        >>> references = [reference1, reference2, reference3]
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len)
+        1.0
+    In case a hypothesis translation is shorter than the references, penalty is
+    applied.
+        >>> references = [['a'] * 28, ['a'] * 28]
+        >>> hypothesis = ['a'] * 12
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len)
+        0.2635971381157267
+    The length of the closest reference is used to compute the penalty. If the
+    length of a hypothesis is 12, and the reference lengths are 13 and 2, the
+    penalty is applied because the hypothesis length (12) is less then the
+    closest reference length (13).
+        >>> references = [['a'] * 13, ['a'] * 2]
+        >>> hypothesis = ['a'] * 12
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len) # doctest: +ELLIPSIS
+        0.9200...
+    The brevity penalty doesn't depend on reference order. More importantly,
+    when two reference sentences are at the same distance, the shortest
+    reference sentence length is used.
+        >>> references = [['a'] * 13, ['a'] * 11]
+        >>> hypothesis = ['a'] * 12
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> bp1 = brevity_penalty(closest_ref_len, hyp_len)
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(reversed(references), hyp_len)
+        >>> bp2 = brevity_penalty(closest_ref_len, hyp_len)
+        >>> bp1 == bp2 == 1
+        True
+    A test example from mteval-v13a.pl (starting from the line 705):
+        >>> references = [['a'] * 11, ['a'] * 8]
+        >>> hypothesis = ['a'] * 7
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len) # doctest: +ELLIPSIS
+        0.8668...
+        >>> references = [['a'] * 11, ['a'] * 8, ['a'] * 6, ['a'] * 7]
+        >>> hypothesis = ['a'] * 7
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len)
+        1.0
+    :param hyp_len: The length of the hypothesis for a single sentence OR the
+    sum of all the hypotheses' lengths for a corpus
+    :type hyp_len: int
+    :param closest_ref_len: The length of the closest reference for a single
+    hypothesis OR the sum of all the closest references for every hypotheses.
+    :type closest_ref_len: int
+    :return: BLEU's brevity penalty.
+    :rtype: float
+    """
+    if hyp_len > closest_ref_len:
+        return 1
+    # If hypothesis is empty, brevity penalty = 0 should result in BLEU = 0.0
+    elif hyp_len == 0:
+        return 0
+    else:
+        return math.exp(1 - closest_ref_len / hyp_len)
+
+
+class SmoothingFunction:
+    """
+    This is an implementation of the smoothing techniques
+    for segment-level BLEU scores that was presented in
+    Boxing Chen and Collin Cherry (2014) A Systematic Comparison of
+    Smoothing Techniques for Sentence-Level BLEU. In WMT14.
+    http://acl2014.org/acl2014/W14-33/pdf/W14-3346.pdf
+    """
+
+    def __init__(self, epsilon=0.1, alpha=5, k=5):
+        """
+        This will initialize the parameters required for the various smoothing
+        techniques, the default values are set to the numbers used in the
+        experiments from Chen and Cherry (2014).
+        >>> hypothesis1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which', 'ensures',
+        ...                 'that', 'the', 'military', 'always', 'obeys', 'the',
+        ...                 'commands', 'of', 'the', 'party']
+        >>> reference1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'that', 'ensures',
+        ...               'that', 'the', 'military', 'will', 'forever', 'heed',
+        ...               'Party', 'commands']
+        >>> chencherry = SmoothingFunction()
+        >>> print(sentence_bleu([reference1], hypothesis1)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method0)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method1)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method2)) # doctest: +ELLIPSIS
+        0.4489...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method3)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method4)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method5)) # doctest: +ELLIPSIS
+        0.4905...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method6)) # doctest: +ELLIPSIS
+        0.4135...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method7)) # doctest: +ELLIPSIS
+        0.4905...
+        :param epsilon: the epsilon value use in method 1
+        :type epsilon: float
+        :param alpha: the alpha value use in method 6
+        :type alpha: int
+        :param k: the k value use in method 4
+        :type k: int
+        """
+        self.epsilon = epsilon
+        self.alpha = alpha
+        self.k = k
+
+    def method0(self, p_n, *args, **kwargs):
+        """
+        No smoothing.
+        """
+        p_n_new = []
+        for i, p_i in enumerate(p_n):
+            if p_i.numerator != 0:
+                p_n_new.append(p_i)
+            else:
+                _msg = str(
+                    "\nThe hypothesis contains 0 counts of {}-gram overlaps.\n"
+                    "Therefore the BLEU score evaluates to 0, independently of\n"
+                    "how many N-gram overlaps of lower order it contains.\n"
+                    "Consider using lower n-gram order or use "
+                    "SmoothingFunction()"
+                ).format(i + 1)
+                warnings.warn(_msg)
+                # When numerator==0 where denonminator==0 or !=0, the result
+                # for the precision score should be equal to 0 or undefined.
+                # Due to BLEU geometric mean computation in logarithm space,
+                # we we need to take the return sys.float_info.min such that
+                # math.log(sys.float_info.min) returns a 0 precision score.
+                p_n_new.append(sys.float_info.min)
+        return p_n_new
+
+    def method1(self, p_n, *args, **kwargs):
+        """
+        Smoothing method 1: Add *epsilon* counts to precision with 0 counts.
+        """
+        return [
+            (p_i.numerator + self.epsilon) / p_i.denominator
+            if p_i.numerator == 0
+            else p_i
+            for p_i in p_n
+        ]
+
+    def method2(self, p_n, *args, **kwargs):
+        """
+        Smoothing method 2: Add 1 to both numerator and denominator from
+        Chin-Yew Lin and Franz Josef Och (2004) Automatic evaluation of
+        machine translation quality using longest common subsequence and
+        skip-bigram statistics. In ACL04.
+        """
+        return [
+            Fraction(p_i.numerator + 1, p_i.denominator + 1, _normalize=False)
+            for p_i in p_n
+        ]
+
+    def method3(self, p_n, *args, **kwargs):
+        """
+        Smoothing method 3: NIST geometric sequence smoothing
+        The smoothing is computed by taking 1 / ( 2^k ), instead of 0, for each
+        precision score whose matching n-gram count is null.
+        k is 1 for the first 'n' value for which the n-gram match count is null/
+        For example, if the text contains:
+         - one 2-gram match
+         - and (consequently) two 1-gram matches
+        the n-gram count for each individual precision score would be:
+         - n=1  =>  prec_count = 2     (two unigrams)
+         - n=2  =>  prec_count = 1     (one bigram)
+         - n=3  =>  prec_count = 1/2   (no trigram,  taking 'smoothed' value of 1 / ( 2^k ), with k=1)
+         - n=4  =>  prec_count = 1/4   (no fourgram, taking 'smoothed' value of 1 / ( 2^k ), with k=2)
+        """
+        incvnt = 1  # From the mteval-v13a.pl, it's referred to as k.
+        for i, p_i in enumerate(p_n):
+            if p_i.numerator == 0:
+                p_n[i] = 1 / (2 ** incvnt * p_i.denominator)
+                incvnt += 1
+        return p_n
+
+    def method4(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 4:
+        Shorter translations may have inflated precision values due to having
+        smaller denominators; therefore, we give them proportionally
+        smaller smoothed counts. Instead of scaling to 1/(2^k), Chen and Cherry
+        suggests dividing by 1/ln(len(T)), where T is the length of the translation.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        for i, p_i in enumerate(p_n):
+            if p_i.numerator == 0 and hyp_len != 0:
+                incvnt = i + 1 * self.k / math.log(
+                    hyp_len
+                )  # Note that this K is different from the K from NIST.
+                p_n[i] = incvnt / p_i.denominator
+        return p_n
+
+    def method5(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 5:
+        The matched counts for similar values of n should be similar. To a
+        calculate the n-gram matched count, it averages the n−1, n and n+1 gram
+        matched counts.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        m = {}
+        # Requires an precision value for an addition ngram order.
+        p_n_plus1 = p_n + [modified_precision(references, hypothesis, 5)]
+        m[-1] = p_n[0] + 1
+        for i, p_i in enumerate(p_n):
+            p_n[i] = (m[i - 1] + p_i + p_n_plus1[i + 1]) / 3
+            m[i] = p_n[i]
+        return p_n
+
+    def method6(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 6:
+        Interpolates the maximum likelihood estimate of the precision *p_n* with
+        a prior estimate *pi0*. The prior is estimated by assuming that the ratio
+        between pn and pn−1 will be the same as that between pn−1 and pn−2; from
+        Gao and He (2013) Training MRF-Based Phrase Translation Models using
+        Gradient Ascent. In NAACL.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        # This smoothing only works when p_1 and p_2 is non-zero.
+        # Raise an error with an appropriate message when the input is too short
+        # to use this smoothing technique.
+        assert p_n[2], "This smoothing method requires non-zero precision for bigrams."
+        for i, p_i in enumerate(p_n):
+            if i in [0, 1]:  # Skips the first 2 orders of ngrams.
+                continue
+            else:
+                pi0 = 0 if p_n[i - 2] == 0 else p_n[i - 1] ** 2 / p_n[i - 2]
+                # No. of ngrams in translation that matches the reference.
+                m = p_i.numerator
+                # No. of ngrams in translation.
+                l = sum(1 for _ in ngrams(hypothesis, i + 1))
+                # Calculates the interpolated precision.
+                p_n[i] = (m + self.alpha * pi0) / (l + self.alpha)
+        return p_n
+
+    def method7(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 7:
+        Interpolates methods 4 and 5.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        p_n = self.method4(p_n, references, hypothesis, hyp_len)
+        p_n = self.method5(p_n, references, hypothesis, hyp_len)
+        return p_n

codebleu.py

@@ -0,0 +1,135 @@
+# Copyright 2020 The HuggingFace Datasets Authors and the current dataset script contributor.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""CodeBLEU metric."""
+
+import evaluate
+import datasets
+
+#these were added to fix evaluate load of dependencies
+from .bleu import corpus_bleu
+from .utils import pad_sequence
+from .weighted_ngram_match import ngrams
+from .syntax_match import calc_syntax_match
+from .parser_DFG import DFG_python
+from .parser_utils import tree_to_token_index
+from .dataflow_match import calc_dataflow_match
+
+from .my_codebleu import calc_codebleu
+
+
+# TODO: Add BibTeX citation
+_CITATION = """\
+@InProceedings{huggingface:module,
+title = {CodeBLEU: A Metric for Evaluating Code Generation},
+authors={Sedykh, Ivan},
+year={2022}
+}
+"""
+
+# TODO: Add description of the module here
+_DESCRIPTION = """\
+This new module is an adaptation of the original CodeBLEU metric from CodexGLUE benchmark 
+for evaluating code generation.
+"""
+
+
+# TODO: Add description of the arguments of the module here
+_KWARGS_DESCRIPTION = """
+Calculates how good are predictions given some references, using certain scores
+Args:
+    predictions: list of predictions to score. Each predictions
+        should be a string with tokens separated by spaces.
+    references: list of lists of references. Each list 
+        should contain len(predictions) items.
+    lang: programming language in ['java','js','c_sharp','php','go','python','ruby']
+    tokenizer: tokenizer function str -> List[str], Defaults to lambda s: s.split()
+    params: str, weights for averaging(see CodeBLEU paper). 
+        Defaults to equal weights "0.25,0.25,0.25,0.25".
+Returns:
+    CodeBLEU: resulting score,
+    ngram_match_score: See paper CodeBLEU,
+    weighted_ngram_match_score: See paper CodeBLEU,
+    syntax_match_score: See paper CodeBLEU,
+    dataflow_match_score: See paper CodeBLEU,
+Examples:
+
+    >>> codebleu = evaluate.load("my_new_module")
+    >>> results = my_new_module.compute(references=[0, 1], predictions=[0, 1])
+    >>> print(results)
+    {'accuracy': 1.0}
+"""
+
+# TODO: Define external resources urls if needed
+# BAD_WORDS_URL = "http://url/to/external/resource/bad_words.txt"
+
+
+@evaluate.utils.file_utils.add_start_docstrings(_DESCRIPTION, _KWARGS_DESCRIPTION)
+class codebleu(evaluate.Metric):
+    """CodeBLEU metric from CodexGLUE"""
+
+    def _info(self):
+        # TODO: Specifies the evaluate.EvaluationModuleInfo object
+        return evaluate.MetricInfo(
+            # This is the description that will appear on the modules page.
+            module_type="metric",
+            description=_DESCRIPTION,
+            citation=_CITATION,
+            inputs_description=_KWARGS_DESCRIPTION,
+            # This defines the format of each prediction and reference
+            features=[
+                datasets.Features(
+                    {
+                        "predictions": datasets.Value("string", id="sequence"),
+                        "references": datasets.Sequence(datasets.Value("string", id="sequence"), id="references"),
+                    }
+                ),
+                datasets.Features(
+                    {
+                        "predictions": datasets.Value("string", id="sequence"),
+                        "references": datasets.Value("string", id="sequence"),
+                    }
+                ),                
+            ],
+            # Homepage of the module for documentation
+            homepage="",
+            # Additional links to the codebase or references
+            codebase_urls=[],
+            reference_urls=[
+                "https://github.com/microsoft/CodeXGLUE/tree/main/Code-Code/code-to-code-trans/evaluator",
+                "https://arxiv.org/abs/2009.10297",
+            ],
+        )
+
+    def _download_and_prepare(self, dl_manager):
+        """Optional: download external resources useful to compute the scores"""
+        # TODO: Download external resources if needed
+        # source CodeBLEU/parser/build.sh
+        # print(dl_manager)
+        self.kw_dir = dl_manager.download_and_extract("keywords.tar.gz")
+        print("Downloaded keywords to", self.kw_dir)
+        self.langso_dir = dl_manager.download("my-languages.so")
+        print("Downloaded languages.so to", self.langso_dir)
+
+    def _compute(self, predictions, references, lang = "python", tokenizer=None, params="0.25,0.25,0.25,0.25"):
+        """Returns the scores"""
+        res = calc_codebleu(
+            predictions=predictions,
+            references=references,
+            lang=lang,
+            tokenizer=tokenizer,
+            params=params,
+            kw_dir = self.kw_dir,
+            langso_dir = self.langso_dir
+        )
+        return res

dataflow_match.py

@@ -0,0 +1,145 @@
+# Copyright (c) Microsoft Corporation. 
+# Licensed under the MIT license.
+
+import os
+from .parser_DFG import DFG_python,DFG_java,DFG_ruby,DFG_go,DFG_php,DFG_javascript,DFG_csharp
+from .parser_utils import (remove_comments_and_docstrings,
+                   tree_to_token_index,
+                   index_to_code_token,
+                   tree_to_variable_index)
+from tree_sitter import Language, Parser
+import pdb
+
+dfg_function={
+    'python':DFG_python,
+    'java':DFG_java,
+    'ruby':DFG_ruby,
+    'go':DFG_go,
+    'php':DFG_php,
+    'javascript':DFG_javascript,
+    'c_sharp':DFG_csharp,
+}
+
+def calc_dataflow_match(references, candidate, lang):
+    return corpus_dataflow_match([references], [candidate], lang)
+
+def corpus_dataflow_match(references, candidates, lang, langso_dir):   
+    LANGUAGE = Language(langso_dir, lang)
+    parser = Parser()
+    parser.set_language(LANGUAGE)
+    parser = [parser,dfg_function[lang]]
+    match_count = 0
+    total_count = 0
+
+    for i in range(len(candidates)):
+        references_sample = references[i]
+        candidate = candidates[i] 
+        for reference in references_sample:
+            try:
+                candidate=remove_comments_and_docstrings(candidate,'java')
+            except:
+                pass    
+            try:
+                reference=remove_comments_and_docstrings(reference,'java')
+            except:
+                pass  
+
+            cand_dfg = get_data_flow(candidate, parser)
+            ref_dfg = get_data_flow(reference, parser)
+            
+            normalized_cand_dfg = normalize_dataflow(cand_dfg)
+            normalized_ref_dfg = normalize_dataflow(ref_dfg)
+
+            if len(normalized_ref_dfg) > 0:
+                total_count += len(normalized_ref_dfg)
+                for dataflow in normalized_ref_dfg:
+                    if dataflow in normalized_cand_dfg:
+                            match_count += 1
+                            normalized_cand_dfg.remove(dataflow)  
+    if total_count == 0:
+        # print("WARNING: There is no reference data-flows extracted from the whole corpus, and the data-flow match score degenerates to 0. Please consider ignoring this score.")
+        # return 0
+        print("WARNING: There is no reference data-flows extracted from the whole corpus, and the data-flow match score degenerates to None")
+        return None       
+    score = match_count / total_count
+    return score
+
+def get_data_flow(code, parser):
+    try:
+        tree = parser[0].parse(bytes(code,'utf8'))    
+        root_node = tree.root_node  
+        tokens_index=tree_to_token_index(root_node)     
+        code=code.split('\n')
+        code_tokens=[index_to_code_token(x,code) for x in tokens_index]  
+        index_to_code={}
+        for idx,(index,code) in enumerate(zip(tokens_index,code_tokens)):
+            index_to_code[index]=(idx,code)  
+        try:
+            DFG,_=parser[1](root_node,index_to_code,{}) 
+        except:
+            DFG=[]
+        DFG=sorted(DFG,key=lambda x:x[1])
+        indexs=set()
+        for d in DFG:
+            if len(d[-1])!=0:
+                indexs.add(d[1])
+            for x in d[-1]:
+                indexs.add(x)
+        new_DFG=[]
+        for d in DFG:
+            if d[1] in indexs:
+                new_DFG.append(d)
+        codes=code_tokens
+        dfg=new_DFG
+    except:
+        codes=code.split()
+        dfg=[]
+    #merge nodes
+    dic={}
+    for d in dfg:
+        if d[1] not in dic:
+            dic[d[1]]=d
+        else:
+            dic[d[1]]=(d[0],d[1],d[2],list(set(dic[d[1]][3]+d[3])),list(set(dic[d[1]][4]+d[4])))
+    DFG=[]
+    for d in dic:
+        DFG.append(dic[d])
+    dfg=DFG
+    return dfg
+
+def normalize_dataflow_item(dataflow_item):
+    var_name = dataflow_item[0]
+    var_pos = dataflow_item[1]
+    relationship = dataflow_item[2]
+    par_vars_name_list = dataflow_item[3]
+    par_vars_pos_list = dataflow_item[4]
+
+    var_names = list(set(par_vars_name_list+[var_name]))
+    norm_names = {}
+    for i in range(len(var_names)):
+        norm_names[var_names[i]] = 'var_'+str(i)
+
+    norm_var_name = norm_names[var_name]
+    relationship = dataflow_item[2]
+    norm_par_vars_name_list = [norm_names[x] for x in par_vars_name_list]
+
+    return (norm_var_name, relationship, norm_par_vars_name_list)
+
+def normalize_dataflow(dataflow):
+    var_dict = {}
+    i = 0
+    normalized_dataflow = []
+    for item in dataflow:
+        var_name = item[0]
+        relationship = item[2]
+        par_vars_name_list = item[3]
+        for name in par_vars_name_list:
+            if name not in var_dict:
+                var_dict[name] = 'var_'+str(i)
+                i += 1
+        if var_name not in var_dict:
+            var_dict[var_name] = 'var_'+str(i)
+            i+= 1
+        normalized_dataflow.append((var_dict[var_name], relationship, [var_dict[x] for x in par_vars_name_list]))
+    return normalized_dataflow
+    

keywords.tar.gz

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:beec11ed55f5a88fa77399b54f1127b50e9b393ad2a060fb0d8d7e3af16014a5
+size 917

my_codebleu.py

@@ -0,0 +1,80 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT license.
+
+# -*- coding:utf-8 -*-
+import os
+import logging
+from . import bleu
+from . import weighted_ngram_match
+from . import syntax_match
+from . import dataflow_match
+
+
+def calc_codebleu(predictions, references, lang, tokenizer=None, params='0.25,0.25,0.25,0.25', kw_dir = ".", langso_dir = "."):
+    """_summary_
+
+    Args:
+        predictions (list[str]): list of predictions
+        references (list[str]): list of lists with references
+        lang (str): ['java','js','c_sharp','php','go','python','ruby']
+        tokenizer (callable): tokenizer function, Defaults to lambda s: s.split()
+        params (str, optional): Defaults to '0.25,0.25,0.25,0.25'.
+    """
+
+    alpha, beta, gamma, theta = [float(x) for x in params.split(',')]
+
+    # preprocess inputs
+    references = [[x.strip() for x in ref] for ref in references]
+    hypothesis = [x.strip() for x in predictions]
+
+    if not len(references) == len(hypothesis):
+        raise ValueError
+
+    # calculate ngram match (BLEU)
+    if tokenizer is None:
+        tokenizer = lambda s: s.split()
+
+    tokenized_hyps = [tokenizer(x) for x in hypothesis]
+    tokenized_refs = [[tokenizer(x) for x in reference]
+                      for reference in references]
+
+    ngram_match_score = bleu.corpus_bleu(tokenized_refs, tokenized_hyps)
+
+    # calculate weighted ngram match
+    keywords = [x.strip() for x in open(kw_dir + '/keywords/' + lang +
+                                        '.txt', 'r', encoding='utf-8').readlines()]
+
+    def make_weights(reference_tokens, key_word_list):
+        return {token: 1 if token in key_word_list else 0.2
+                for token in reference_tokens}
+    tokenized_refs_with_weights = [[[reference_tokens, make_weights(reference_tokens, keywords)]
+                                    for reference_tokens in reference] for reference in tokenized_refs]
+
+    weighted_ngram_match_score = weighted_ngram_match.corpus_bleu(
+        tokenized_refs_with_weights, tokenized_hyps)
+
+    # calculate syntax match
+    syntax_match_score = syntax_match.corpus_syntax_match(
+        references, hypothesis, lang, langso_dir)
+
+    # calculate dataflow match
+    dataflow_match_score = dataflow_match.corpus_dataflow_match(
+        references, hypothesis, lang, langso_dir)
+
+    # print('ngram match: {0}, weighted ngram match: {1}, syntax_match: {2}, dataflow_match: {3}'.
+        #   format(ngram_match_score, weighted_ngram_match_score, syntax_match_score, dataflow_match_score))
+
+    code_bleu_score = alpha*ngram_match_score\
+        + beta*weighted_ngram_match_score\
+        + gamma*syntax_match_score\
+        + theta*(dataflow_match_score or 1)
+
+    # print('CodeBLEU score: ', code_bleu_score)
+
+    return {
+        'CodeBLEU': code_bleu_score,
+        'ngram_match_score': ngram_match_score,
+        'weighted_ngram_match_score': weighted_ngram_match_score,
+        'syntax_match_score': syntax_match_score,
+        'dataflow_match_score': dataflow_match_score
+    }

parser_DFG.py

@@ -0,0 +1,1184 @@
+# Copyright (c) Microsoft Corporation. 
+# Licensed under the MIT license.
+
+from tree_sitter import Language, Parser
+from .parser_utils import (remove_comments_and_docstrings,
+                   tree_to_token_index,
+                   index_to_code_token,
+                   tree_to_variable_index)
+
+
+def DFG_python(root_node,index_to_code,states):
+    assignment=['assignment','augmented_assignment','for_in_clause']
+    if_statement=['if_statement']
+    for_statement=['for_statement']
+    while_statement=['while_statement']
+    do_first_statement=['for_in_clause'] 
+    def_statement=['default_parameter']
+    states=states.copy() 
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':        
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('value')
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_python(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states        
+    elif root_node.type in assignment:
+        if root_node.type=='for_in_clause':
+            right_nodes=[root_node.children[-1]]
+            left_nodes=[root_node.child_by_field_name('left')]
+        else:
+            if root_node.child_by_field_name('right') is None:
+                return [],states
+            left_nodes=[x for x in root_node.child_by_field_name('left').children if x.type!=',']
+            right_nodes=[x for x in root_node.child_by_field_name('right').children if x.type!=',']
+            if len(right_nodes)!=len(left_nodes):
+                left_nodes=[root_node.child_by_field_name('left')]
+                right_nodes=[root_node.child_by_field_name('right')]
+            if len(left_nodes)==0:
+                left_nodes=[root_node.child_by_field_name('left')]
+            if len(right_nodes)==0:
+                right_nodes=[root_node.child_by_field_name('right')]
+        DFG=[]
+        for node in right_nodes:
+            temp,states=DFG_python(node,index_to_code,states)
+            DFG+=temp
+            
+        for left_node,right_node in zip(left_nodes,right_nodes):
+            left_tokens_index=tree_to_variable_index(left_node,index_to_code)
+            right_tokens_index=tree_to_variable_index(right_node,index_to_code)
+            temp=[]
+            for token1_index in left_tokens_index:
+                idx1,code1=index_to_code[token1_index]
+                temp.append((code1,idx1,'computedFrom',[index_to_code[x][1] for x in right_tokens_index],
+                             [index_to_code[x][0] for x in right_tokens_index]))
+                states[code1]=[idx1]
+            DFG+=temp        
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in ['elif_clause','else_clause']:
+                temp,current_states=DFG_python(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                temp,new_states=DFG_python(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        if tag is False:
+            others_states.append(states)
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for i in range(2):
+            right_nodes=[x for x in root_node.child_by_field_name('right').children if x.type!=',']
+            left_nodes=[x for x in root_node.child_by_field_name('left').children if x.type!=',']
+            if len(right_nodes)!=len(left_nodes):
+                left_nodes=[root_node.child_by_field_name('left')]
+                right_nodes=[root_node.child_by_field_name('right')]
+            if len(left_nodes)==0:
+                left_nodes=[root_node.child_by_field_name('left')]
+            if len(right_nodes)==0:
+                right_nodes=[root_node.child_by_field_name('right')]
+            for node in right_nodes:
+                temp,states=DFG_python(node,index_to_code,states)
+                DFG+=temp
+            for left_node,right_node in zip(left_nodes,right_nodes):
+                left_tokens_index=tree_to_variable_index(left_node,index_to_code)
+                right_tokens_index=tree_to_variable_index(right_node,index_to_code)
+                temp=[]
+                for token1_index in left_tokens_index:
+                    idx1,code1=index_to_code[token1_index]
+                    temp.append((code1,idx1,'computedFrom',[index_to_code[x][1] for x in right_tokens_index],
+                                 [index_to_code[x][0] for x in right_tokens_index]))
+                    states[code1]=[idx1]
+                DFG+=temp   
+            if  root_node.children[-1].type=="block":
+                temp,states=DFG_python(root_node.children[-1],index_to_code,states)
+                DFG+=temp 
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in while_statement:  
+        DFG=[]
+        for i in range(2):
+            for child in root_node.children:
+                temp,states=DFG_python(child,index_to_code,states)
+                DFG+=temp    
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states        
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_python(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_python(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+        
+
+def DFG_java(root_node,index_to_code,states):
+    assignment=['assignment_expression']
+    def_statement=['variable_declarator']
+    increment_statement=['update_expression']
+    if_statement=['if_statement','else']
+    for_statement=['for_statement']
+    enhanced_for_statement=['enhanced_for_statement']
+    while_statement=['while_statement']
+    do_first_statement=[]    
+    states=states.copy()
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('value')
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_java(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in assignment:
+        left_nodes=root_node.child_by_field_name('left')
+        right_nodes=root_node.child_by_field_name('right')
+        DFG=[]
+        temp,states=DFG_java(right_nodes,index_to_code,states)
+        DFG+=temp            
+        name_indexs=tree_to_variable_index(left_nodes,index_to_code)
+        value_indexs=tree_to_variable_index(right_nodes,index_to_code)        
+        for index1 in name_indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in value_indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]   
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in increment_statement:
+        DFG=[]
+        indexs=tree_to_variable_index(root_node,index_to_code)
+        for index1 in indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]
+        return sorted(DFG,key=lambda x:x[1]),states   
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        flag=False
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in if_statement and flag is False:
+                temp,current_states=DFG_java(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                flag=True
+                temp,new_states=DFG_java(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        if tag is False:
+            others_states.append(states)
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for child in root_node.children:
+            temp,states=DFG_java(child,index_to_code,states)
+            DFG+=temp
+        flag=False
+        for child in root_node.children:
+            if flag:
+                temp,states=DFG_java(child,index_to_code,states)
+                DFG+=temp                
+            elif child.type=="local_variable_declaration":
+                flag=True
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in enhanced_for_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('value')
+        body=root_node.child_by_field_name('body')
+        DFG=[]
+        for i in range(2):
+            temp,states=DFG_java(value,index_to_code,states)
+            DFG+=temp       
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)        
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            temp,states=DFG_java(body,index_to_code,states)
+            DFG+=temp                       
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in while_statement:  
+        DFG=[]
+        for i in range(2):
+            for child in root_node.children:
+                temp,states=DFG_java(child,index_to_code,states)
+                DFG+=temp    
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states        
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_java(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_java(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+
+def DFG_csharp(root_node,index_to_code,states):
+    assignment=['assignment_expression']
+    def_statement=['variable_declarator']
+    increment_statement=['postfix_unary_expression']
+    if_statement=['if_statement','else']
+    for_statement=['for_statement']
+    enhanced_for_statement=['for_each_statement']
+    while_statement=['while_statement']
+    do_first_statement=[]    
+    states=states.copy()
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        if len(root_node.children)==2:
+            name=root_node.children[0]
+            value=root_node.children[1]
+        else:
+            name=root_node.children[0]
+            value=None
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_csharp(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in assignment:
+        left_nodes=root_node.child_by_field_name('left')
+        right_nodes=root_node.child_by_field_name('right')
+        DFG=[]
+        temp,states=DFG_csharp(right_nodes,index_to_code,states)
+        DFG+=temp            
+        name_indexs=tree_to_variable_index(left_nodes,index_to_code)
+        value_indexs=tree_to_variable_index(right_nodes,index_to_code)        
+        for index1 in name_indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in value_indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]   
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in increment_statement:
+        DFG=[]
+        indexs=tree_to_variable_index(root_node,index_to_code)
+        for index1 in indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]
+        return sorted(DFG,key=lambda x:x[1]),states   
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        flag=False
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in if_statement and flag is False:
+                temp,current_states=DFG_csharp(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                flag=True
+                temp,new_states=DFG_csharp(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        if tag is False:
+            others_states.append(states)
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for child in root_node.children:
+            temp,states=DFG_csharp(child,index_to_code,states)
+            DFG+=temp
+        flag=False
+        for child in root_node.children:
+            if flag:
+                temp,states=DFG_csharp(child,index_to_code,states)
+                DFG+=temp                
+            elif child.type=="local_variable_declaration":
+                flag=True
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in enhanced_for_statement:
+        name=root_node.child_by_field_name('left')
+        value=root_node.child_by_field_name('right')
+        body=root_node.child_by_field_name('body')
+        DFG=[]
+        for i in range(2):
+            temp,states=DFG_csharp(value,index_to_code,states)
+            DFG+=temp       
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)        
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            temp,states=DFG_csharp(body,index_to_code,states)
+            DFG+=temp                       
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in while_statement:  
+        DFG=[]
+        for i in range(2):
+            for child in root_node.children:
+                temp,states=DFG_csharp(child,index_to_code,states)
+                DFG+=temp    
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states        
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_csharp(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_csharp(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+
+
+    
+    
+def DFG_ruby(root_node,index_to_code,states):
+    assignment=['assignment','operator_assignment']
+    if_statement=['if','elsif','else','unless','when']
+    for_statement=['for']
+    while_statement=['while_modifier','until']
+    do_first_statement=[] 
+    def_statement=['keyword_parameter']
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        states=states.copy()
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('value')
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_ruby(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states        
+    elif root_node.type in assignment:
+        left_nodes=[x for x in root_node.child_by_field_name('left').children if x.type!=',']
+        right_nodes=[x for x in root_node.child_by_field_name('right').children if x.type!=',']
+        if len(right_nodes)!=len(left_nodes):
+            left_nodes=[root_node.child_by_field_name('left')]
+            right_nodes=[root_node.child_by_field_name('right')]
+        if len(left_nodes)==0:
+            left_nodes=[root_node.child_by_field_name('left')]
+        if len(right_nodes)==0:
+            right_nodes=[root_node.child_by_field_name('right')]
+        if root_node.type=="operator_assignment":
+            left_nodes=[root_node.children[0]]
+            right_nodes=[root_node.children[-1]]
+
+        DFG=[]
+        for node in right_nodes:
+            temp,states=DFG_ruby(node,index_to_code,states)
+            DFG+=temp
+            
+        for left_node,right_node in zip(left_nodes,right_nodes):
+            left_tokens_index=tree_to_variable_index(left_node,index_to_code)
+            right_tokens_index=tree_to_variable_index(right_node,index_to_code)
+            temp=[]
+            for token1_index in left_tokens_index:
+                idx1,code1=index_to_code[token1_index]
+                temp.append((code1,idx1,'computedFrom',[index_to_code[x][1] for x in right_tokens_index],
+                             [index_to_code[x][0] for x in right_tokens_index]))
+                states[code1]=[idx1]
+            DFG+=temp        
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in if_statement:
+                temp,current_states=DFG_ruby(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                temp,new_states=DFG_ruby(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        if tag is False:
+            others_states.append(states)
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for i in range(2):
+            left_nodes=[root_node.child_by_field_name('pattern')]
+            right_nodes=[root_node.child_by_field_name('value')]
+            assert len(right_nodes)==len(left_nodes)
+            for node in right_nodes:
+                temp,states=DFG_ruby(node,index_to_code,states)
+                DFG+=temp
+            for left_node,right_node in zip(left_nodes,right_nodes):
+                left_tokens_index=tree_to_variable_index(left_node,index_to_code)
+                right_tokens_index=tree_to_variable_index(right_node,index_to_code)
+                temp=[]
+                for token1_index in left_tokens_index:
+                    idx1,code1=index_to_code[token1_index]
+                    temp.append((code1,idx1,'computedFrom',[index_to_code[x][1] for x in right_tokens_index],
+                                 [index_to_code[x][0] for x in right_tokens_index]))
+                    states[code1]=[idx1]
+                DFG+=temp 
+            temp,states=DFG_ruby(root_node.child_by_field_name('body'),index_to_code,states)
+            DFG+=temp 
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in while_statement:  
+        DFG=[]
+        for i in range(2):
+            for child in root_node.children:
+                temp,states=DFG_ruby(child,index_to_code,states)
+                DFG+=temp    
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states        
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_ruby(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_ruby(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+
+def DFG_go(root_node,index_to_code,states):
+    assignment=['assignment_statement',]
+    def_statement=['var_spec']
+    increment_statement=['inc_statement']
+    if_statement=['if_statement','else']
+    for_statement=['for_statement']
+    enhanced_for_statement=[]
+    while_statement=[]
+    do_first_statement=[]    
+    states=states.copy()
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('value')
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_go(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in assignment:
+        left_nodes=root_node.child_by_field_name('left')
+        right_nodes=root_node.child_by_field_name('right')
+        DFG=[]
+        temp,states=DFG_go(right_nodes,index_to_code,states)
+        DFG+=temp            
+        name_indexs=tree_to_variable_index(left_nodes,index_to_code)
+        value_indexs=tree_to_variable_index(right_nodes,index_to_code)        
+        for index1 in name_indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in value_indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]   
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in increment_statement:
+        DFG=[]
+        indexs=tree_to_variable_index(root_node,index_to_code)
+        for index1 in indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]
+        return sorted(DFG,key=lambda x:x[1]),states   
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        flag=False
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in if_statement and flag is False:
+                temp,current_states=DFG_go(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                flag=True
+                temp,new_states=DFG_go(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        if tag is False:
+            others_states.append(states)
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in states:
+            if key not in new_states:
+                new_states[key]=states[key]
+            else:
+                new_states[key]+=states[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for child in root_node.children:
+            temp,states=DFG_go(child,index_to_code,states)
+            DFG+=temp
+        flag=False
+        for child in root_node.children:
+            if flag:
+                temp,states=DFG_go(child,index_to_code,states)
+                DFG+=temp                
+            elif child.type=="for_clause":
+                if child.child_by_field_name('update') is not None:
+                    temp,states=DFG_go(child.child_by_field_name('update'),index_to_code,states)
+                    DFG+=temp                 
+                flag=True
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_go(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_go(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+
+    
+    
+
+def DFG_php(root_node,index_to_code,states):
+    assignment=['assignment_expression','augmented_assignment_expression']
+    def_statement=['simple_parameter']
+    increment_statement=['update_expression']
+    if_statement=['if_statement','else_clause']
+    for_statement=['for_statement']
+    enhanced_for_statement=['foreach_statement']
+    while_statement=['while_statement']
+    do_first_statement=[]    
+    states=states.copy()
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('default_value')
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_php(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in assignment:
+        left_nodes=root_node.child_by_field_name('left')
+        right_nodes=root_node.child_by_field_name('right')
+        DFG=[]
+        temp,states=DFG_php(right_nodes,index_to_code,states)
+        DFG+=temp            
+        name_indexs=tree_to_variable_index(left_nodes,index_to_code)
+        value_indexs=tree_to_variable_index(right_nodes,index_to_code)        
+        for index1 in name_indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in value_indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]   
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in increment_statement:
+        DFG=[]
+        indexs=tree_to_variable_index(root_node,index_to_code)
+        for index1 in indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]
+        return sorted(DFG,key=lambda x:x[1]),states   
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        flag=False
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in if_statement and flag is False:
+                temp,current_states=DFG_php(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                flag=True
+                temp,new_states=DFG_php(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in states:
+            if key not in new_states:
+                new_states[key]=states[key]
+            else:
+                new_states[key]+=states[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for child in root_node.children:
+            temp,states=DFG_php(child,index_to_code,states)
+            DFG+=temp
+        flag=False
+        for child in root_node.children:
+            if flag:
+                temp,states=DFG_php(child,index_to_code,states)
+                DFG+=temp                
+            elif child.type=="assignment_expression":               
+                flag=True
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in enhanced_for_statement:
+        name=None
+        value=None
+        for child in root_node.children:
+            if child.type=='variable_name' and value is None:
+                value=child
+            elif child.type=='variable_name' and name is None:
+                name=child
+                break
+        body=root_node.child_by_field_name('body')
+        DFG=[]
+        for i in range(2):
+            temp,states=DFG_php(value,index_to_code,states)
+            DFG+=temp       
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)        
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            temp,states=DFG_php(body,index_to_code,states)
+            DFG+=temp                       
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in while_statement:  
+        DFG=[]
+        for i in range(2):
+            for child in root_node.children:
+                temp,states=DFG_php(child,index_to_code,states)
+                DFG+=temp    
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states        
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_php(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_php(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+
+
+def DFG_javascript(root_node,index_to_code,states):
+    assignment=['assignment_pattern','augmented_assignment_expression']
+    def_statement=['variable_declarator']
+    increment_statement=['update_expression']
+    if_statement=['if_statement','else']
+    for_statement=['for_statement']
+    enhanced_for_statement=[]
+    while_statement=['while_statement']
+    do_first_statement=[]    
+    states=states.copy()
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        idx,code=index_to_code[(root_node.start_point,root_node.end_point)]
+        if root_node.type==code:
+            return [],states
+        elif code in states:
+            return [(code,idx,'comesFrom',[code],states[code].copy())],states
+        else:
+            if root_node.type=='identifier':
+                states[code]=[idx]
+            return [(code,idx,'comesFrom',[],[])],states
+    elif root_node.type in def_statement:
+        name=root_node.child_by_field_name('name')
+        value=root_node.child_by_field_name('value')
+        DFG=[]
+        if value is None:
+            indexs=tree_to_variable_index(name,index_to_code)
+            for index in indexs:
+                idx,code=index_to_code[index]
+                DFG.append((code,idx,'comesFrom',[],[]))
+                states[code]=[idx]
+            return sorted(DFG,key=lambda x:x[1]),states
+        else:
+            name_indexs=tree_to_variable_index(name,index_to_code)
+            value_indexs=tree_to_variable_index(value,index_to_code)
+            temp,states=DFG_javascript(value,index_to_code,states)
+            DFG+=temp            
+            for index1 in name_indexs:
+                idx1,code1=index_to_code[index1]
+                for index2 in value_indexs:
+                    idx2,code2=index_to_code[index2]
+                    DFG.append((code1,idx1,'comesFrom',[code2],[idx2]))
+                states[code1]=[idx1]   
+            return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in assignment:
+        left_nodes=root_node.child_by_field_name('left')
+        right_nodes=root_node.child_by_field_name('right')
+        DFG=[]
+        temp,states=DFG_javascript(right_nodes,index_to_code,states)
+        DFG+=temp            
+        name_indexs=tree_to_variable_index(left_nodes,index_to_code)
+        value_indexs=tree_to_variable_index(right_nodes,index_to_code)        
+        for index1 in name_indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in value_indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]   
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in increment_statement:
+        DFG=[]
+        indexs=tree_to_variable_index(root_node,index_to_code)
+        for index1 in indexs:
+            idx1,code1=index_to_code[index1]
+            for index2 in indexs:
+                idx2,code2=index_to_code[index2]
+                DFG.append((code1,idx1,'computedFrom',[code2],[idx2]))
+            states[code1]=[idx1]
+        return sorted(DFG,key=lambda x:x[1]),states   
+    elif root_node.type in if_statement:
+        DFG=[]
+        current_states=states.copy()
+        others_states=[]
+        flag=False
+        tag=False
+        if 'else' in root_node.type:
+            tag=True
+        for child in root_node.children:
+            if 'else' in child.type:
+                tag=True
+            if child.type not in if_statement and flag is False:
+                temp,current_states=DFG_javascript(child,index_to_code,current_states)
+                DFG+=temp
+            else:
+                flag=True
+                temp,new_states=DFG_javascript(child,index_to_code,states)
+                DFG+=temp
+                others_states.append(new_states)
+        others_states.append(current_states)
+        if tag is False:
+            others_states.append(states)        
+        new_states={}
+        for dic in others_states:
+            for key in dic:
+                if key not in new_states:
+                    new_states[key]=dic[key].copy()
+                else:
+                    new_states[key]+=dic[key]
+        for key in states:
+            if key not in new_states:
+                new_states[key]=states[key]
+            else:
+                new_states[key]+=states[key]
+        for key in new_states:
+            new_states[key]=sorted(list(set(new_states[key])))
+        return sorted(DFG,key=lambda x:x[1]),new_states
+    elif root_node.type in for_statement:
+        DFG=[]
+        for child in root_node.children:
+            temp,states=DFG_javascript(child,index_to_code,states)
+            DFG+=temp
+        flag=False
+        for child in root_node.children:
+            if flag:
+                temp,states=DFG_javascript(child,index_to_code,states)
+                DFG+=temp                
+            elif child.type=="variable_declaration":               
+                flag=True
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states
+    elif root_node.type in while_statement:  
+        DFG=[]
+        for i in range(2):
+            for child in root_node.children:
+                temp,states=DFG_javascript(child,index_to_code,states)
+                DFG+=temp    
+        dic={}
+        for x in DFG:
+            if (x[0],x[1],x[2]) not in dic:
+                dic[(x[0],x[1],x[2])]=[x[3],x[4]]
+            else:
+                dic[(x[0],x[1],x[2])][0]=list(set(dic[(x[0],x[1],x[2])][0]+x[3]))
+                dic[(x[0],x[1],x[2])][1]=sorted(list(set(dic[(x[0],x[1],x[2])][1]+x[4])))
+        DFG=[(x[0],x[1],x[2],y[0],y[1]) for x,y in sorted(dic.items(),key=lambda t:t[0][1])]
+        return sorted(DFG,key=lambda x:x[1]),states    
+    else:
+        DFG=[]
+        for child in root_node.children:
+            if child.type in do_first_statement:
+                temp,states=DFG_javascript(child,index_to_code,states)
+                DFG+=temp
+        for child in root_node.children:
+            if child.type not in do_first_statement:
+                temp,states=DFG_javascript(child,index_to_code,states)
+                DFG+=temp
+        
+        return sorted(DFG,key=lambda x:x[1]),states
+
+
+     

parser_utils.py

@@ -0,0 +1,101 @@
+# Copyright (c) Microsoft Corporation. 
+# Licensed under the MIT license.
+
+import re
+from io import StringIO
+import tokenize
+def remove_comments_and_docstrings(source,lang):
+    if lang in ['python']:
+        """
+        Returns 'source' minus comments and docstrings.
+        """
+        io_obj = StringIO(source)
+        out = ""
+        prev_toktype = tokenize.INDENT
+        last_lineno = -1
+        last_col = 0
+        for tok in tokenize.generate_tokens(io_obj.readline):
+            token_type = tok[0]
+            token_string = tok[1]
+            start_line, start_col = tok[2]
+            end_line, end_col = tok[3]
+            ltext = tok[4]
+            if start_line > last_lineno:
+                last_col = 0
+            if start_col > last_col:
+                out += (" " * (start_col - last_col))
+            # Remove comments:
+            if token_type == tokenize.COMMENT:
+                pass
+            # This series of conditionals removes docstrings:
+            elif token_type == tokenize.STRING:
+                if prev_toktype != tokenize.INDENT:
+            # This is likely a docstring; double-check we're not inside an operator:
+                    if prev_toktype != tokenize.NEWLINE:
+                        if start_col > 0:
+                            out += token_string
+            else:
+                out += token_string
+            prev_toktype = token_type
+            last_col = end_col
+            last_lineno = end_line
+        temp=[]
+        for x in out.split('\n'):
+            if x.strip()!="":
+                temp.append(x)
+        return '\n'.join(temp)
+    elif lang in ['ruby']:
+        return source
+    else:
+        def replacer(match):
+            s = match.group(0)
+            if s.startswith('/'):
+                return " " # note: a space and not an empty string
+            else:
+                return s
+        pattern = re.compile(
+            r'//.*?$|/\*.*?\*/|\'(?:\\.|[^\\\'])*\'|"(?:\\.|[^\\"])*"',
+            re.DOTALL | re.MULTILINE
+        )
+        temp=[]
+        for x in re.sub(pattern, replacer, source).split('\n'):
+            if x.strip()!="":
+                temp.append(x)
+        return '\n'.join(temp)
+
+def tree_to_token_index(root_node):
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        return [(root_node.start_point,root_node.end_point)]
+    else:
+        code_tokens=[]
+        for child in root_node.children:
+            code_tokens+=tree_to_token_index(child)
+        return code_tokens
+    
+def tree_to_variable_index(root_node,index_to_code):
+    if (len(root_node.children)==0 or root_node.type in ['string_literal','string','character_literal']) and root_node.type!='comment':
+        index=(root_node.start_point,root_node.end_point)
+        _,code=index_to_code[index]
+        if root_node.type!=code:
+            return [(root_node.start_point,root_node.end_point)]
+        else:
+            return []
+    else:
+        code_tokens=[]
+        for child in root_node.children:
+            code_tokens+=tree_to_variable_index(child,index_to_code)
+        return code_tokens    
+
+def index_to_code_token(index,code):
+    start_point=index[0]
+    end_point=index[1]
+    if start_point[0]==end_point[0]:
+        s=code[start_point[0]][start_point[1]:end_point[1]]
+    else:
+        s=""
+        s+=code[start_point[0]][start_point[1]:]
+        for i in range(start_point[0]+1,end_point[0]):
+            s+=code[i]
+        s+=code[end_point[0]][:end_point[1]]   
+    return s
+   

requirements.txt

@@ -0,0 +1,3 @@
+evaluate
+tree-sitter==0.2.2
+gradio

syntax_match.py

@@ -0,0 +1,75 @@
+# Copyright (c) Microsoft Corporation. 
+# Licensed under the MIT license.
+
+import os
+from .parser_DFG import DFG_python,DFG_java,DFG_ruby,DFG_go,DFG_php,DFG_javascript,DFG_csharp
+from .parser_utils import (remove_comments_and_docstrings,
+                   tree_to_token_index,
+                   index_to_code_token,
+                   tree_to_variable_index)
+from tree_sitter import Language, Parser
+
+dfg_function={
+    'python':DFG_python,
+    'java':DFG_java,
+    'ruby':DFG_ruby,
+    'go':DFG_go,
+    'php':DFG_php,
+    'javascript':DFG_javascript,
+    'c_sharp':DFG_csharp,
+}
+
+def calc_syntax_match(references, candidate, lang):
+    return corpus_syntax_match([references], [candidate], lang)
+
+def corpus_syntax_match(references, candidates, lang, langso_dir):
+    # print(os.listdir())
+    JAVA_LANGUAGE = Language(langso_dir, lang)
+    parser = Parser()
+    parser.set_language(JAVA_LANGUAGE)
+    match_count = 0
+    total_count = 0
+
+    for i in range(len(candidates)):
+        references_sample = references[i]
+        candidate = candidates[i] 
+        for reference in references_sample:
+            try:
+                candidate=remove_comments_and_docstrings(candidate,'java')
+            except:
+                pass    
+            try:
+                reference=remove_comments_and_docstrings(reference,'java')
+            except:
+                pass  
+
+            candidate_tree = parser.parse(bytes(candidate,'utf8')).root_node
+
+            reference_tree = parser.parse(bytes(reference,'utf8')).root_node
+
+            def get_all_sub_trees(root_node):
+                node_stack = []
+                sub_tree_sexp_list = []
+                depth = 1
+                node_stack.append([root_node, depth])
+                while len(node_stack) != 0:
+                    cur_node, cur_depth = node_stack.pop()
+                    sub_tree_sexp_list.append([cur_node.sexp(), cur_depth])
+                    for child_node in cur_node.children:
+                        if len(child_node.children) != 0:
+                            depth = cur_depth + 1
+                            node_stack.append([child_node, depth])
+                return sub_tree_sexp_list
+            cand_sexps = [x[0] for x in get_all_sub_trees(candidate_tree)]
+            ref_sexps = get_all_sub_trees(reference_tree)
+
+            # print(cand_sexps)
+            # print(ref_sexps)
+            
+            for sub_tree, depth in ref_sexps:
+                if sub_tree in cand_sexps:
+                     match_count += 1
+            total_count += len(ref_sexps)          
+       
+    score = match_count / total_count
+    return score

tests.py

@@ -0,0 +1,17 @@
+test_cases = [
+    {
+        "predictions": [0, 0],
+        "references": [1, 1],
+        "result": {"metric_score": 0}
+    },
+    {
+        "predictions": [1, 1],
+        "references": [1, 1],
+        "result": {"metric_score": 1}
+    },
+    {
+        "predictions": [1, 0],
+        "references": [1, 1],
+        "result": {"metric_score": 0.5}
+    }
+]

utils.py

@@ -0,0 +1,106 @@
+# Natural Language Toolkit: Utility functions
+#
+# Copyright (C) 2001-2020 NLTK Project
+# Author: Steven Bird <[email protected]>
+# URL: <http://nltk.org/>
+# For license information, see LICENSE.TXT
+
+from itertools import chain
+
+def pad_sequence(
+    sequence,
+    n,
+    pad_left=False,
+    pad_right=False,
+    left_pad_symbol=None,
+    right_pad_symbol=None,
+):
+    """
+    Returns a padded sequence of items before ngram extraction.
+        >>> list(pad_sequence([1,2,3,4,5], 2, pad_left=True, pad_right=True, left_pad_symbol='<s>', right_pad_symbol='</s>'))
+        ['<s>', 1, 2, 3, 4, 5, '</s>']
+        >>> list(pad_sequence([1,2,3,4,5], 2, pad_left=True, left_pad_symbol='<s>'))
+        ['<s>', 1, 2, 3, 4, 5]
+        >>> list(pad_sequence([1,2,3,4,5], 2, pad_right=True, right_pad_symbol='</s>'))
+        [1, 2, 3, 4, 5, '</s>']
+    :param sequence: the source data to be padded
+    :type sequence: sequence or iter
+    :param n: the degree of the ngrams
+    :type n: int
+    :param pad_left: whether the ngrams should be left-padded
+    :type pad_left: bool
+    :param pad_right: whether the ngrams should be right-padded
+    :type pad_right: bool
+    :param left_pad_symbol: the symbol to use for left padding (default is None)
+    :type left_pad_symbol: any
+    :param right_pad_symbol: the symbol to use for right padding (default is None)
+    :type right_pad_symbol: any
+    :rtype: sequence or iter
+    """
+    sequence = iter(sequence)
+    if pad_left:
+        sequence = chain((left_pad_symbol,) * (n - 1), sequence)
+    if pad_right:
+        sequence = chain(sequence, (right_pad_symbol,) * (n - 1))
+    return sequence
+
+
+# add a flag to pad the sequence so we get peripheral ngrams?
+
+
+def ngrams(
+    sequence,
+    n,
+    pad_left=False,
+    pad_right=False,
+    left_pad_symbol=None,
+    right_pad_symbol=None,
+):
+    """
+    Return the ngrams generated from a sequence of items, as an iterator.
+    For example:
+        >>> from nltk.util import ngrams
+        >>> list(ngrams([1,2,3,4,5], 3))
+        [(1, 2, 3), (2, 3, 4), (3, 4, 5)]
+    Wrap with list for a list version of this function.  Set pad_left
+    or pad_right to true in order to get additional ngrams:
+        >>> list(ngrams([1,2,3,4,5], 2, pad_right=True))
+        [(1, 2), (2, 3), (3, 4), (4, 5), (5, None)]
+        >>> list(ngrams([1,2,3,4,5], 2, pad_right=True, right_pad_symbol='</s>'))
+        [(1, 2), (2, 3), (3, 4), (4, 5), (5, '</s>')]
+        >>> list(ngrams([1,2,3,4,5], 2, pad_left=True, left_pad_symbol='<s>'))
+        [('<s>', 1), (1, 2), (2, 3), (3, 4), (4, 5)]
+        >>> list(ngrams([1,2,3,4,5], 2, pad_left=True, pad_right=True, left_pad_symbol='<s>', right_pad_symbol='</s>'))
+        [('<s>', 1), (1, 2), (2, 3), (3, 4), (4, 5), (5, '</s>')]
+    :param sequence: the source data to be converted into ngrams
+    :type sequence: sequence or iter
+    :param n: the degree of the ngrams
+    :type n: int
+    :param pad_left: whether the ngrams should be left-padded
+    :type pad_left: bool
+    :param pad_right: whether the ngrams should be right-padded
+    :type pad_right: bool
+    :param left_pad_symbol: the symbol to use for left padding (default is None)
+    :type left_pad_symbol: any
+    :param right_pad_symbol: the symbol to use for right padding (default is None)
+    :type right_pad_symbol: any
+    :rtype: sequence or iter
+    """
+    sequence = pad_sequence(
+        sequence, n, pad_left, pad_right, left_pad_symbol, right_pad_symbol
+    )
+
+    history = []
+    while n > 1:
+        # PEP 479, prevent RuntimeError from being raised when StopIteration bubbles out of generator
+        try:
+            next_item = next(sequence)
+        except StopIteration:
+            # no more data, terminate the generator
+            return
+        history.append(next_item)
+        n -= 1
+    for item in sequence:
+        history.append(item)
+        yield tuple(history)
+        del history[0]

weighted_ngram_match.py

@@ -0,0 +1,558 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) Microsoft Corporation. 
+# Licensed under the MIT license.
+
+# Natural Language Toolkit: BLEU Score
+#
+# Copyright (C) 2001-2020 NLTK Project
+# Authors: Chin Yee Lee, Hengfeng Li, Ruxin Hou, Calvin Tanujaya Lim
+# Contributors: Björn Mattsson, Dmitrijs Milajevs, Liling Tan
+# URL: <http://nltk.org/>
+# For license information, see LICENSE.TXT
+
+"""BLEU score implementation."""
+
+import math
+import sys
+from fractions import Fraction
+import warnings
+from collections import Counter
+
+from .utils import ngrams
+import pdb
+
+
+def sentence_bleu(
+    references,
+    hypothesis,
+    weights=(0.25, 0.25, 0.25, 0.25),
+    smoothing_function=None,
+    auto_reweigh=False,
+):
+    """
+    Calculate BLEU score (Bilingual Evaluation Understudy) from
+    Papineni, Kishore, Salim Roukos, Todd Ward, and Wei-Jing Zhu. 2002.
+    "BLEU: a method for automatic evaluation of machine translation."
+    In Proceedings of ACL. http://www.aclweb.org/anthology/P02-1040.pdf
+    >>> hypothesis1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which',
+    ...               'ensures', 'that', 'the', 'military', 'always',
+    ...               'obeys', 'the', 'commands', 'of', 'the', 'party']
+    >>> hypothesis2 = ['It', 'is', 'to', 'insure', 'the', 'troops',
+    ...               'forever', 'hearing', 'the', 'activity', 'guidebook',
+    ...               'that', 'party', 'direct']
+    >>> reference1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
+    ...               'ensures', 'that', 'the', 'military', 'will', 'forever',
+    ...               'heed', 'Party', 'commands']
+    >>> reference2 = ['It', 'is', 'the', 'guiding', 'principle', 'which',
+    ...               'guarantees', 'the', 'military', 'forces', 'always',
+    ...               'being', 'under', 'the', 'command', 'of', 'the',
+    ...               'Party']
+    >>> reference3 = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
+    ...               'army', 'always', 'to', 'heed', 'the', 'directions',
+    ...               'of', 'the', 'party']
+    >>> sentence_bleu([reference1, reference2, reference3], hypothesis1) # doctest: +ELLIPSIS
+    0.5045...
+    If there is no ngrams overlap for any order of n-grams, BLEU returns the
+    value 0. This is because the precision for the order of n-grams without
+    overlap is 0, and the geometric mean in the final BLEU score computation
+    multiplies the 0 with the precision of other n-grams. This results in 0
+    (independently of the precision of the othe n-gram orders). The following
+    example has zero 3-gram and 4-gram overlaps:
+    >>> round(sentence_bleu([reference1, reference2, reference3], hypothesis2),4) # doctest: +ELLIPSIS
+    0.0
+    To avoid this harsh behaviour when no ngram overlaps are found a smoothing
+    function can be used.
+    >>> chencherry = SmoothingFunction()
+    >>> sentence_bleu([reference1, reference2, reference3], hypothesis2,
+    ...     smoothing_function=chencherry.method1) # doctest: +ELLIPSIS
+    0.0370...
+    The default BLEU calculates a score for up to 4-grams using uniform
+    weights (this is called BLEU-4). To evaluate your translations with
+    higher/lower order ngrams, use customized weights. E.g. when accounting
+    for up to 5-grams with uniform weights (this is called BLEU-5) use:
+    >>> weights = (1./5., 1./5., 1./5., 1./5., 1./5.)
+    >>> sentence_bleu([reference1, reference2, reference3], hypothesis1, weights) # doctest: +ELLIPSIS
+    0.3920...
+    :param references: reference sentences
+    :type references: list(list(str))
+    :param hypothesis: a hypothesis sentence
+    :type hypothesis: list(str)
+    :param weights: weights for unigrams, bigrams, trigrams and so on
+    :type weights: list(float)
+    :param smoothing_function:
+    :type smoothing_function: SmoothingFunction
+    :param auto_reweigh: Option to re-normalize the weights uniformly.
+    :type auto_reweigh: bool
+    :return: The sentence-level BLEU score.
+    :rtype: float
+    """
+    return corpus_bleu(
+        [references], [hypothesis], weights, smoothing_function, auto_reweigh
+    )
+
+
+def corpus_bleu(
+    list_of_references,
+    hypotheses,
+    weights=(0.25, 0.25, 0.25, 0.25),
+    smoothing_function=None,
+    auto_reweigh=False,
+):
+    """
+    Calculate a single corpus-level BLEU score (aka. system-level BLEU) for all
+    the hypotheses and their respective references.
+    Instead of averaging the sentence level BLEU scores (i.e. marco-average
+    precision), the original BLEU metric (Papineni et al. 2002) accounts for
+    the micro-average precision (i.e. summing the numerators and denominators
+    for each hypothesis-reference(s) pairs before the division).
+    >>> hyp1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which',
+    ...         'ensures', 'that', 'the', 'military', 'always',
+    ...         'obeys', 'the', 'commands', 'of', 'the', 'party']
+    >>> ref1a = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
+    ...          'ensures', 'that', 'the', 'military', 'will', 'forever',
+    ...          'heed', 'Party', 'commands']
+    >>> ref1b = ['It', 'is', 'the', 'guiding', 'principle', 'which',
+    ...          'guarantees', 'the', 'military', 'forces', 'always',
+    ...          'being', 'under', 'the', 'command', 'of', 'the', 'Party']
+    >>> ref1c = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
+    ...          'army', 'always', 'to', 'heed', 'the', 'directions',
+    ...          'of', 'the', 'party']
+    >>> hyp2 = ['he', 'read', 'the', 'book', 'because', 'he', 'was',
+    ...         'interested', 'in', 'world', 'history']
+    >>> ref2a = ['he', 'was', 'interested', 'in', 'world', 'history',
+    ...          'because', 'he', 'read', 'the', 'book']
+    >>> list_of_references = [[ref1a, ref1b, ref1c], [ref2a]]
+    >>> hypotheses = [hyp1, hyp2]
+    >>> corpus_bleu(list_of_references, hypotheses) # doctest: +ELLIPSIS
+    0.5920...
+    The example below show that corpus_bleu() is different from averaging
+    sentence_bleu() for hypotheses
+    >>> score1 = sentence_bleu([ref1a, ref1b, ref1c], hyp1)
+    >>> score2 = sentence_bleu([ref2a], hyp2)
+    >>> (score1 + score2) / 2 # doctest: +ELLIPSIS
+    0.6223...
+    :param list_of_references: a corpus of lists of reference sentences, w.r.t. hypotheses
+    :type list_of_references: list(list(list(str)))
+    :param hypotheses: a list of hypothesis sentences
+    :type hypotheses: list(list(str))
+    :param weights: weights for unigrams, bigrams, trigrams and so on
+    :type weights: list(float)
+    :param smoothing_function:
+    :type smoothing_function: SmoothingFunction
+    :param auto_reweigh: Option to re-normalize the weights uniformly.
+    :type auto_reweigh: bool
+    :return: The corpus-level BLEU score.
+    :rtype: float
+    """
+    # Before proceeding to compute BLEU, perform sanity checks.
+
+    p_numerators = Counter()  # Key = ngram order, and value = no. of ngram matches.
+    p_denominators = Counter()  # Key = ngram order, and value = no. of ngram in ref.
+    hyp_lengths, ref_lengths = 0, 0
+
+    assert len(list_of_references) == len(hypotheses), (
+        "The number of hypotheses and their reference(s) should be the " "same "
+    )
+
+    # Iterate through each hypothesis and their corresponding references.
+    for references, hypothesis in zip(list_of_references, hypotheses):
+        # For each order of ngram, calculate the numerator and
+        # denominator for the corpus-level modified precision.
+        for i, _ in enumerate(weights, start=1):
+            p_i_numeraotr, p_i_denominator = modified_recall(references, hypothesis, i)
+            p_numerators[i] += p_i_numeraotr
+            p_denominators[i] += p_i_denominator
+
+        # Calculate the hypothesis length and the closest reference length.
+        # Adds them to the corpus-level hypothesis and reference counts.
+        hyp_len = len(hypothesis)
+        hyp_lengths += hyp_len
+        ref_lengths += closest_ref_length(references, hyp_len)
+
+    # Calculate corpus-level brevity penalty.
+    bp = brevity_penalty(ref_lengths, hyp_lengths)
+
+    # Uniformly re-weighting based on maximum hypothesis lengths if largest
+    # order of n-grams < 4 and weights is set at default.
+    if auto_reweigh:
+        if hyp_lengths < 4 and weights == (0.25, 0.25, 0.25, 0.25):
+            weights = (1 / hyp_lengths,) * hyp_lengths
+
+    # Collects the various recall values for the different ngram orders.
+    p_n = [
+        (p_numerators[i], p_denominators[i])
+        for i, _ in enumerate(weights, start=1)
+    ]
+
+    # Returns 0 if there's no matching n-grams
+    # We only need to check for p_numerators[1] == 0, since if there's
+    # no unigrams, there won't be any higher order ngrams.
+    if p_numerators[1] == 0:
+        return 0
+
+    # If there's no smoothing, set use method0 from SmoothinFunction class.
+    if not smoothing_function:
+        smoothing_function = SmoothingFunction().method1
+    # Smoothen the modified precision.
+    # Note: smoothing_function() may convert values into floats;
+    #       it tries to retain the Fraction object as much as the
+    #       smoothing method allows.
+    p_n = smoothing_function(
+        p_n, references=references, hypothesis=hypothesis, hyp_len=hyp_lengths
+    )
+    # pdb.set_trace()
+    s = (w_i * math.log(p_i[0]/p_i[1]) for w_i, p_i in zip(weights, p_n))
+    s = bp * math.exp(math.fsum(s))
+    return s
+
+
+def modified_recall(references, hypothesis, n):
+    """
+    Calculate modified ngram recall.
+    :param references: A list of reference translations.
+    :type references: list(list(str))
+    :param hypothesis: A hypothesis translation.
+    :type hypothesis: list(str)
+    :param n: The ngram order.
+    :type n: int
+    :return: BLEU's modified precision for the nth order ngram.
+    :rtype: Fraction
+    """
+    # Extracts all ngrams in hypothesis
+    # Set an empty Counter if hypothesis is empty.
+    # pdb.set_trace()
+    numerator = 0
+    denominator = 0
+
+    counts = Counter(ngrams(hypothesis, n)) if len(hypothesis) >= n else Counter()
+    # Extract a union of references' counts.
+    # max_counts = reduce(or_, [Counter(ngrams(ref, n)) for ref in references])
+    max_counts = {}
+    for reference_and_weights in references:
+        reference = reference_and_weights[0]
+        weights = reference_and_weights[1]
+        reference_counts = (
+            Counter(ngrams(reference, n)) if len(reference) >= n else Counter()
+        )
+        # for ngram in reference_counts:
+        #     max_counts[ngram] = max(max_counts.get(ngram, 0), counts[ngram])
+        clipped_counts = {
+            ngram: min(count, counts[ngram]) for ngram, count in reference_counts.items()
+        }
+        # reweight
+        if n == 1 and len(weights) == len(reference_counts):
+            def weighted_sum(weights, counts):
+                sum_counts = 0
+                for ngram, count in counts.items():
+                    sum_counts += count * (weights[ngram[0]] if ngram[0] in weights else 1)
+                return sum_counts
+
+            numerator += weighted_sum(weights, clipped_counts)
+            denominator += max(1, weighted_sum(weights, reference_counts))
+
+        else:
+            numerator += sum(clipped_counts.values())
+            denominator += max(1, sum(reference_counts.values()))
+
+        # # Assigns the intersection between hypothesis and references' counts.
+        # clipped_counts = {
+        #     ngram: min(count, max_counts[ngram]) for ngram, count in counts.items()
+        # }
+
+        # numerator += sum(clipped_counts.values())
+        # # Ensures that denominator is minimum 1 to avoid ZeroDivisionError.
+        # # Usually this happens when the ngram order is > len(reference).
+        # denominator += max(1, sum(counts.values()))
+
+    #return Fraction(numerator, denominator, _normalize=False)
+    return numerator, denominator
+
+
+def closest_ref_length(references, hyp_len):
+    """
+    This function finds the reference that is the closest length to the
+    hypothesis. The closest reference length is referred to as *r* variable
+    from the brevity penalty formula in Papineni et. al. (2002)
+    :param references: A list of reference translations.
+    :type references: list(list(str))
+    :param hyp_len: The length of the hypothesis.
+    :type hyp_len: int
+    :return: The length of the reference that's closest to the hypothesis.
+    :rtype: int
+    """
+    ref_lens = (len(reference) for reference in references)
+    closest_ref_len = min(
+        ref_lens, key=lambda ref_len: (abs(ref_len - hyp_len), ref_len)
+    )
+    return closest_ref_len
+
+
+def brevity_penalty(closest_ref_len, hyp_len):
+    """
+    Calculate brevity penalty.
+    As the modified n-gram precision still has the problem from the short
+    length sentence, brevity penalty is used to modify the overall BLEU
+    score according to length.
+    An example from the paper. There are three references with length 12, 15
+    and 17. And a concise hypothesis of the length 12. The brevity penalty is 1.
+        >>> reference1 = list('aaaaaaaaaaaa')      # i.e. ['a'] * 12
+        >>> reference2 = list('aaaaaaaaaaaaaaa')   # i.e. ['a'] * 15
+        >>> reference3 = list('aaaaaaaaaaaaaaaaa') # i.e. ['a'] * 17
+        >>> hypothesis = list('aaaaaaaaaaaa')      # i.e. ['a'] * 12
+        >>> references = [reference1, reference2, reference3]
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len)
+        1.0
+    In case a hypothesis translation is shorter than the references, penalty is
+    applied.
+        >>> references = [['a'] * 28, ['a'] * 28]
+        >>> hypothesis = ['a'] * 12
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len)
+        0.2635971381157267
+    The length of the closest reference is used to compute the penalty. If the
+    length of a hypothesis is 12, and the reference lengths are 13 and 2, the
+    penalty is applied because the hypothesis length (12) is less then the
+    closest reference length (13).
+        >>> references = [['a'] * 13, ['a'] * 2]
+        >>> hypothesis = ['a'] * 12
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len) # doctest: +ELLIPSIS
+        0.9200...
+    The brevity penalty doesn't depend on reference order. More importantly,
+    when two reference sentences are at the same distance, the shortest
+    reference sentence length is used.
+        >>> references = [['a'] * 13, ['a'] * 11]
+        >>> hypothesis = ['a'] * 12
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> bp1 = brevity_penalty(closest_ref_len, hyp_len)
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(reversed(references), hyp_len)
+        >>> bp2 = brevity_penalty(closest_ref_len, hyp_len)
+        >>> bp1 == bp2 == 1
+        True
+    A test example from mteval-v13a.pl (starting from the line 705):
+        >>> references = [['a'] * 11, ['a'] * 8]
+        >>> hypothesis = ['a'] * 7
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len) # doctest: +ELLIPSIS
+        0.8668...
+        >>> references = [['a'] * 11, ['a'] * 8, ['a'] * 6, ['a'] * 7]
+        >>> hypothesis = ['a'] * 7
+        >>> hyp_len = len(hypothesis)
+        >>> closest_ref_len =  closest_ref_length(references, hyp_len)
+        >>> brevity_penalty(closest_ref_len, hyp_len)
+        1.0
+    :param hyp_len: The length of the hypothesis for a single sentence OR the
+    sum of all the hypotheses' lengths for a corpus
+    :type hyp_len: int
+    :param closest_ref_len: The length of the closest reference for a single
+    hypothesis OR the sum of all the closest references for every hypotheses.
+    :type closest_ref_len: int
+    :return: BLEU's brevity penalty.
+    :rtype: float
+    """
+    if hyp_len > closest_ref_len:
+        return 1
+    # If hypothesis is empty, brevity penalty = 0 should result in BLEU = 0.0
+    elif hyp_len == 0:
+        return 0
+    else:
+        return math.exp(1 - closest_ref_len / hyp_len)
+
+
+class SmoothingFunction:
+    """
+    This is an implementation of the smoothing techniques
+    for segment-level BLEU scores that was presented in
+    Boxing Chen and Collin Cherry (2014) A Systematic Comparison of
+    Smoothing Techniques for Sentence-Level BLEU. In WMT14.
+    http://acl2014.org/acl2014/W14-33/pdf/W14-3346.pdf
+    """
+
+    def __init__(self, epsilon=0.1, alpha=5, k=5):
+        """
+        This will initialize the parameters required for the various smoothing
+        techniques, the default values are set to the numbers used in the
+        experiments from Chen and Cherry (2014).
+        >>> hypothesis1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which', 'ensures',
+        ...                 'that', 'the', 'military', 'always', 'obeys', 'the',
+        ...                 'commands', 'of', 'the', 'party']
+        >>> reference1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'that', 'ensures',
+        ...               'that', 'the', 'military', 'will', 'forever', 'heed',
+        ...               'Party', 'commands']
+        >>> chencherry = SmoothingFunction()
+        >>> print(sentence_bleu([reference1], hypothesis1)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method0)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method1)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method2)) # doctest: +ELLIPSIS
+        0.4489...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method3)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method4)) # doctest: +ELLIPSIS
+        0.4118...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method5)) # doctest: +ELLIPSIS
+        0.4905...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method6)) # doctest: +ELLIPSIS
+        0.4135...
+        >>> print(sentence_bleu([reference1], hypothesis1, smoothing_function=chencherry.method7)) # doctest: +ELLIPSIS
+        0.4905...
+        :param epsilon: the epsilon value use in method 1
+        :type epsilon: float
+        :param alpha: the alpha value use in method 6
+        :type alpha: int
+        :param k: the k value use in method 4
+        :type k: int
+        """
+        self.epsilon = epsilon
+        self.alpha = alpha
+        self.k = k
+
+    def method0(self, p_n, *args, **kwargs):
+        """
+        No smoothing.
+        """
+        p_n_new = []
+        for i, p_i in enumerate(p_n):
+            if p_i[0] != 0:
+                p_n_new.append(p_i)
+            else:
+                _msg = str(
+                    "\nThe hypothesis contains 0 counts of {}-gram overlaps.\n"
+                    "Therefore the BLEU score evaluates to 0, independently of\n"
+                    "how many N-gram overlaps of lower order it contains.\n"
+                    "Consider using lower n-gram order or use "
+                    "SmoothingFunction()"
+                ).format(i + 1)
+                warnings.warn(_msg)
+                # When numerator==0 where denonminator==0 or !=0, the result
+                # for the precision score should be equal to 0 or undefined.
+                # Due to BLEU geometric mean computation in logarithm space,
+                # we we need to take the return sys.float_info.min such that
+                # math.log(sys.float_info.min) returns a 0 precision score.
+                p_n_new.append(sys.float_info.min)
+        return p_n_new
+
+    def method1(self, p_n, *args, **kwargs):
+        """
+        Smoothing method 1: Add *epsilon* counts to precision with 0 counts.
+        """
+        return [
+            ((p_i[0] + self.epsilon),  p_i[1])
+            if p_i[0] == 0
+            else p_i
+            for p_i in p_n
+        ]
+
+    def method2(self, p_n, *args, **kwargs):
+        """
+        Smoothing method 2: Add 1 to both numerator and denominator from
+        Chin-Yew Lin and Franz Josef Och (2004) Automatic evaluation of
+        machine translation quality using longest common subsequence and
+        skip-bigram statistics. In ACL04.
+        """
+        return [
+            (p_i[0] + 1, p_i[1] + 1)
+            for p_i in p_n
+        ]
+
+    def method3(self, p_n, *args, **kwargs):
+        """
+        Smoothing method 3: NIST geometric sequence smoothing
+        The smoothing is computed by taking 1 / ( 2^k ), instead of 0, for each
+        precision score whose matching n-gram count is null.
+        k is 1 for the first 'n' value for which the n-gram match count is null/
+        For example, if the text contains:
+         - one 2-gram match
+         - and (consequently) two 1-gram matches
+        the n-gram count for each individual precision score would be:
+         - n=1  =>  prec_count = 2     (two unigrams)
+         - n=2  =>  prec_count = 1     (one bigram)
+         - n=3  =>  prec_count = 1/2   (no trigram,  taking 'smoothed' value of 1 / ( 2^k ), with k=1)
+         - n=4  =>  prec_count = 1/4   (no fourgram, taking 'smoothed' value of 1 / ( 2^k ), with k=2)
+        """
+        incvnt = 1  # From the mteval-v13a.pl, it's referred to as k.
+        for i, p_i in enumerate(p_n):
+            if p_i.numerator == 0:
+                p_n[i] = 1 / (2 ** incvnt * p_i.denominator)
+                incvnt += 1
+        return p_n
+
+    def method4(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 4:
+        Shorter translations may have inflated precision values due to having
+        smaller denominators; therefore, we give them proportionally
+        smaller smoothed counts. Instead of scaling to 1/(2^k), Chen and Cherry
+        suggests dividing by 1/ln(len(T)), where T is the length of the translation.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        for i, p_i in enumerate(p_n):
+            if p_i.numerator == 0 and hyp_len != 0:
+                incvnt = i + 1 * self.k / math.log(
+                    hyp_len
+                )  # Note that this K is different from the K from NIST.
+                p_n[i] = incvnt / p_i.denominator
+        return p_n
+
+    def method5(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 5:
+        The matched counts for similar values of n should be similar. To a
+        calculate the n-gram matched count, it averages the n−1, n and n+1 gram
+        matched counts.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        m = {}
+        # Requires an precision value for an addition ngram order.
+        p_n_plus1 = p_n + [modified_precision(references, hypothesis, 5)]
+        m[-1] = p_n[0] + 1
+        for i, p_i in enumerate(p_n):
+            p_n[i] = (m[i - 1] + p_i + p_n_plus1[i + 1]) / 3
+            m[i] = p_n[i]
+        return p_n
+
+    def method6(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 6:
+        Interpolates the maximum likelihood estimate of the precision *p_n* with
+        a prior estimate *pi0*. The prior is estimated by assuming that the ratio
+        between pn and pn−1 will be the same as that between pn−1 and pn−2; from
+        Gao and He (2013) Training MRF-Based Phrase Translation Models using
+        Gradient Ascent. In NAACL.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        # This smoothing only works when p_1 and p_2 is non-zero.
+        # Raise an error with an appropriate message when the input is too short
+        # to use this smoothing technique.
+        assert p_n[2], "This smoothing method requires non-zero precision for bigrams."
+        for i, p_i in enumerate(p_n):
+            if i in [0, 1]:  # Skips the first 2 orders of ngrams.
+                continue
+            else:
+                pi0 = 0 if p_n[i - 2] == 0 else p_n[i - 1] ** 2 / p_n[i - 2]
+                # No. of ngrams in translation that matches the reference.
+                m = p_i.numerator
+                # No. of ngrams in translation.
+                l = sum(1 for _ in ngrams(hypothesis, i + 1))
+                # Calculates the interpolated precision.
+                p_n[i] = (m + self.alpha * pi0) / (l + self.alpha)
+        return p_n
+
+    def method7(self, p_n, references, hypothesis, hyp_len=None, *args, **kwargs):
+        """
+        Smoothing method 7:
+        Interpolates methods 4 and 5.
+        """
+        hyp_len = hyp_len if hyp_len else len(hypothesis)
+        p_n = self.method4(p_n, references, hypothesis, hyp_len)
+        p_n = self.method5(p_n, references, hypothesis, hyp_len)
+        return p_n