"""Python implementation of llama grammar parser directly translated from C++ source file in vendor/llama.cpp/common/grammar-parser.cpp."""
# flake8: noqa
from pathlib import Path
import sys
from ctypes import * # type: ignore
from enum import Enum
from itertools import islice, groupby
from typing import (
Any,
Callable,
Dict,
Set,
Generic,
List,
Optional,
OrderedDict,
TextIO,
Tuple,
TypeVar,
Union,
overload,
)
import llama_cpp.llama_cpp as llama_cpp
# Type aliases
llama_grammar_element = llama_cpp.llama_grammar_element
llama_grammar_element_p = llama_cpp.llama_grammar_element_p
llama_grammar_p = llama_cpp.llama_grammar_p
# Type variables
Ptr = TypeVar("Ptr", bound="const_char_p")
T = TypeVar("T")
U = TypeVar("U")
V = TypeVar("V")
W = TypeVar("W")
class Sentinel:
"""Used to mark the end of a iterator of std::vector & std::map."""
class LlamaGrammar:
"""Keeps reference counts of all the arguments, so that they are not
garbage collected by Python."""
def __del__(self) -> None:
"""Free the grammar pointer when the object is deleted."""
if self.grammar is not None:
llama_cpp.llama_grammar_free(self.grammar)
self.grammar = None
def __init__(
self,
parsed_grammar: "parse_state",
) -> None:
"""Initialize the grammar pointer from the parsed state."""
self._grammar_rules = (
parsed_grammar.c_rules()
) # type: std.vector[std.vector[LlamaGrammarElement]]
self._n_rules = self._grammar_rules.size() # type: int
self._start_rule_index = parsed_grammar.symbol_ids.at("root") # type: int
self.init()
@classmethod
def from_string(cls, grammar: str, verbose: bool = True) -> "LlamaGrammar":
"""Convert a GBNF grammar to a Llama grammar."""
parsed_grammar = parse(const_char_p(grammar)) # type: parse_state
if parsed_grammar.rules.empty():
raise ValueError(
f"{cls.from_string.__name__}: error parsing grammar file: parsed_grammar.rules is empty"
)
if verbose:
print(f"{cls.from_string.__name__} grammar:", file=sys.stderr)
print_grammar(sys.stderr, parsed_grammar)
print(file=sys.stderr)
return cls(parsed_grammar)
@classmethod
def from_json_schema(
cls,
json_schema: str,
verbose: bool = True,
) -> "LlamaGrammar":
"""Convert a JSON schema to a Llama grammar."""
return cls.from_string(json_schema_to_gbnf(json_schema), verbose=verbose)
@classmethod
def from_file(cls, file: Union[str, Path], verbose: bool = True) -> "LlamaGrammar":
try:
with open(file) as f:
grammar = f.read()
except Exception as err:
raise Exception(
f"{cls.from_file.__name__}: error reading grammar file: {err}"
)
if grammar:
return cls.from_string(grammar, verbose=verbose)
raise ValueError(
f"{cls.from_file.__name__}: error parsing grammar file: params_grammer is empty"
)
def init(self) -> None:
# Step 1: Convert LlamaGrammarElement to llama_grammar_element
self._element_lists = [
[
llama_grammar_element(c_int(elem.type.value), c_uint32(elem.value))
for elem in subvector
]
for subvector in self._grammar_rules
] # type: List[List[llama_grammar_element]]
# Step 2: Convert each list to llama_grammar_element array and get pointer
self._element_arrays = [
(llama_grammar_element * len(sublist))(*sublist)
for sublist in self._element_lists
] # type: List[Array[llama_grammar_element]]
# Step 3: Get pointer of each array
self._element_array_pointers = [
cast(subarray, llama_grammar_element_p) for subarray in self._element_arrays
] # type: List[llama_grammar_element_p]
# Step 4: Make array of these pointers and get its pointer
self._rules = (llama_grammar_element_p * len(self._element_array_pointers))(
*self._element_array_pointers
)
self.grammar = llama_cpp.llama_grammar_init(
self._rules, c_size_t(self._n_rules), c_size_t(self._start_rule_index)
)
def reset(self) -> None:
if self.grammar is not None:
llama_cpp.llama_grammar_free(self.grammar)
self.init()
class LlamaGrammarElement:
def __init__(self, type: "llama_gretype", value: int):
self.type = type
self.value = value # Unicode code point or rule ID
class const_char_p:
"""C++ implementation of const char *."""
def __init__(self, value: Union[str, Ptr], move: Optional[int] = None):
if isinstance(value, const_char_p):
# We're copying an existing const_char_p
self.value = value.value
self.pos = value.pos + (move or 0)
return
# We're creating a new const_char_p
self.value = value
self.pos = move or 0
def __str__(self) -> str:
assert self.value is not None, "null pointer"
return self.value[self.pos :]
def __getitem__(self, index: int) -> str:
value = str(self)
return value[index] if index < len(value) else ""
@overload
def __add__(self: Ptr, other: int) -> Ptr:
...
@overload
def __add__(self: Ptr, other: Ptr) -> int:
...
def __add__(self: Ptr, other: Union[int, Ptr]) -> Union[int, Ptr]:
return (
self.__class__(self.value, self.pos + other)
if isinstance(other, int)
else self.pos + other.pos
)
@overload
def __sub__(self: Ptr, other: int) -> Ptr:
...
@overload
def __sub__(self: Ptr, other: Ptr) -> int:
...
def __sub__(self: Ptr, other: Union[int, Ptr]) -> Union[int, Ptr]:
return (
self.__class__(self.value, self.pos - other)
if isinstance(other, int)
else self.pos - other.pos
)
def __eq__(self: Ptr, other: Ptr) -> bool:
assert self.value == other.value, "comparing pointers from different strings"
return self.pos == other.pos
def __lt__(self: Ptr, other: Ptr) -> bool:
assert self.value == other.value, "comparing pointers from different strings"
return self.pos < other.pos
def __gt__(self: Ptr, other: Ptr) -> bool:
assert self.value == other.value, "comparing pointers from different strings"
return self.pos > other.pos
class std:
@staticmethod
def string(ptr: const_char_p, length: Optional[int] = None) -> str:
"""C++ implementation of std::string constructor."""
value = str(ptr)
if length is not None:
value = value[:length]
return value
class vector(Generic[T], List[T]):
"""C++ implementation of std::vector."""
class iterator:
def __init__(self, vector: "std.vector[T]", index: int):
self._vector = vector
self._index = index
self._version = vector._version
def _check_version(self):
if self._version != self._vector._version:
raise RuntimeError("Iterator used after vector was modified.")
def __iter__(self):
return self
def __next__(self) -> T:
self._check_version()
if self._index >= self._vector.size():
raise StopIteration
value = self._vector[self._index]
self._index += 1
return value
def __add__(self, value: int) -> "std.vector[T].iterator":
return self.__class__(self._vector, self._index + value)
def __sub__(self, value: int) -> "std.vector[T].iterator":
return self.__class__(self._vector, self._index - value)
def __init__(self):
self._version = 0
def modify(self):
# This is a bit of a hack to make sure iterators are invalidated
self._version += 1
def push_back(self, value: T) -> None:
self.modify()
self.append(value)
def pop_back(self) -> None:
self.modify()
if not self.empty():
self.pop()
def back(self) -> T:
return self[-1]
def size(self) -> int:
return len(self)
def clear(self) -> None:
self.modify()
super().clear()
def empty(self) -> bool:
return self.size() == 0
def data(self) -> "std.vector[T]":
return self
def resize(
self,
new_size: int,
fill_value_factory: Optional[Callable[[], T]] = None,
) -> None:
if new_size > self.size():
if fill_value_factory is None:
raise ValueError("A fill value factory function must be provided.")
self.reserve(new_size, fill_value_factory)
elif new_size < self.size():
self[:] = self[:new_size]
def reserve(self, capacity: int, fill_value_factory: Callable[[], T]) -> None:
if capacity > self.size():
fill_value = fill_value_factory()
self.extend([fill_value] * (capacity - self.size()))
def front(self) -> T:
if not self.empty():
return self[0]
else:
raise IndexError("Vector is empty.")
def assign(self, count: int, value: T) -> None:
self.clear()
self.extend([value] * count)
def insert(
self,
pos: "std.vector[T].iterator",
first: "std.vector[T].iterator",
last: "std.vector[T].iterator",
) -> None:
self[pos._index : pos._index] = list(
islice(first._vector, first._index, last._index)
)
def begin(self) -> "std.vector[T].iterator":
return self.iterator(self, 0)
def end(self) -> "std.vector[T].iterator":
return self.iterator(self, self.size())
class map(Generic[T, U], OrderedDict[T, U]):
"""C++ implementation of std::map."""
class iterator(Generic[V, W]):
def __init__(self, _map: "std.map[T, U]", key: Union[T, Sentinel]):
self._map = _map
self.iter = iter(_map)
self.key = key
self._advance()
def _sanitize_key(self) -> T:
if isinstance(self.key, Sentinel):
raise StopIteration
return self.key
def _advance(self) -> None:
try:
while next(self.iter) != self.key:
pass
except StopIteration:
self.key = Sentinel()
def __next__(self) -> Tuple[T, U]:
key = self._sanitize_key()
if key in self._map:
value = self._map[key]
self._advance()
return key, value
else:
raise StopIteration
def get(self) -> Tuple[T, U]:
key = self._sanitize_key()
return key, self._map[key]
@property
def first(self) -> T:
return self._sanitize_key()
@property
def second(self) -> U:
return self._map[self._sanitize_key()]
def insert(
self, key: T, value: U
) -> Tuple["std.map[T, U].iterator[T, U]", bool]:
if key in self:
return self.iterator(self, key), False
else:
self[key] = value
return self.iterator(self, key), True
def find(self, key: T) -> "std.map[T, U].iterator[T, U]":
if key in self:
return self.iterator(self, key)
else:
return self.end()
def at(self, key: T) -> U:
if key in self:
return self[key]
else:
raise KeyError("The provided key is not found in the map.")
def erase(self, iterator: "std.map[T, U].iterator[T, U]") -> None:
key = iterator.first
if key in self:
del self[key]
def size(self) -> int:
return len(self)
def empty(self) -> bool:
return self.size() == 0
def lower_bound(self, key: T) -> "std.map[T, U].iterator[T, U]":
try:
keys = sorted(list(self.keys())) # type: ignore
for k in keys:
if k >= key:
return self.iterator(self, k)
raise ValueError("No key found that is not less than the input key")
except TypeError:
raise TypeError("Keys of type T cannot be sorted.")
def begin(self) -> "std.map[T, U].iterator[T, U]":
return self.iterator(self, next(iter(self)))
def end(self) -> "std.map[T, U].iterator[T, U]":
return self.iterator(self, Sentinel())
# // grammar element type
# enum llama_gretype {
# // end of rule definition
# LLAMA_GRETYPE_END = 0,
# // start of alternate definition for rule
# LLAMA_GRETYPE_ALT = 1,
# // non-terminal element: reference to rule
# LLAMA_GRETYPE_RULE_REF = 2,
# // terminal element: character (code point)
# LLAMA_GRETYPE_CHAR = 3,
# // inverse char(s) ([^a], [^a-b] [^abc])
# LLAMA_GRETYPE_CHAR_NOT = 4,
# // modifies a preceding LLAMA_GRETYPE_CHAR or LLAMA_GRETYPE_CHAR_ALT to
# // be an inclusive range ([a-z])
# LLAMA_GRETYPE_CHAR_RNG_UPPER = 5,
# // modifies a preceding LLAMA_GRETYPE_CHAR or
# // LLAMA_GRETYPE_CHAR_RNG_UPPER to add an alternate char to match ([ab], [a-zA])
# LLAMA_GRETYPE_CHAR_ALT = 6,
# };
class llama_gretype(Enum):
"""grammar element type"""
LLAMA_GRETYPE_END = 0 # end of rule definition
LLAMA_GRETYPE_ALT = 1 # start of alternate definition for rule
LLAMA_GRETYPE_RULE_REF = 2 # non-terminal element: reference to rule
LLAMA_GRETYPE_CHAR = 3 # terminal element: character (code point)
LLAMA_GRETYPE_CHAR_NOT = 4 # inverse char(s) ([^a], [^a-b] [^abc])
LLAMA_GRETYPE_CHAR_RNG_UPPER = 5 # modifies a preceding LLAMA_GRETYPE_CHAR or LLAMA_GRETYPE_CHAR_ALT to be an inclusive range ([a-z])
LLAMA_GRETYPE_CHAR_ALT = 6 # modifies a preceding LLAMA_GRETYPE_CHAR or LLAMA_GRETYPE_CHAR_RNG_UPPER to add an alternate char to match ([ab], [a-zA])
# struct parse_state {
# std::map<std::string, uint32_t> symbol_ids;
# std::vector<std::vector<llama_grammar_element>> rules;
# std::vector<const llama_grammar_element *> c_rules();
# };
class parse_state:
def __init__(self):
self.symbol_ids: std.map[str, int] = std.map()
self.rules: std.vector[std.vector[LlamaGrammarElement]] = std.vector()
# std::vector<const llama_grammar_element *> parse_state::c_rules() {
# std::vector<const llama_grammar_element *> ret;
# for (const auto & rule : rules) {
# ret.push_back(rule.data());
# }
# return ret;
# }
def c_rules(self) -> std.vector[std.vector[LlamaGrammarElement]]:
ret = std.vector() # type: std.vector[std.vector[LlamaGrammarElement]]
for rule in self.rules:
ret.push_back(rule.data())
return ret
def __repr__(self) -> str:
return (
f"parse_state(symbol_ids={len(self.symbol_ids)}, rules={len(self.rules)})"
)
# struct llama_grammar {
# const std::vector<std::vector<llama_grammar_element>> rules;
# std::vector<std::vector<const llama_grammar_element *>> stacks;
# };
# class llama_grammar:
# def __init__(
# self,
# rules: std.vector[std.vector[llama_grammar_element]],
# stacks: std.vector[std.vector[llama_grammar_element]],
# ):
# self.rules = rules
# self.stacks = stacks
# uint32_t get_symbol_id(parse_state & state, const char * src, size_t len) {
# uint32_t next_id = static_cast<uint32_t>(state.symbol_ids.size());
# auto result = state.symbol_ids.insert(std::make_pair(std::string(src, len), next_id));
# return result.first->second;
# }
def get_symbol_id(state: parse_state, src: const_char_p, len: int) -> int:
next_id = state.symbol_ids.size() # type: int
result = state.symbol_ids.insert(std.string(src, len), next_id)
return result[0].second # type: ignore
# uint32_t generate_symbol_id(parse_state & state, const std::string & base_name) {
# uint32_t next_id = static_cast<uint32_t>(state.symbol_ids.size());
# state.symbol_ids[base_name + '_' + std::to_string(next_id)] = next_id;
# return next_id;
# }
def generate_symbol_id(state: parse_state, base_name: str) -> int:
next_id = state.symbol_ids.size() # type: int
state.symbol_ids[base_name + "_" + str(next_id)] = next_id
return next_id
# void add_rule(
# parse_state & state,
# uint32_t rule_id,
# const std::vector<llama_grammar_element> & rule) {
# if (state.rules.size() <= rule_id) {
# state.rules.resize(rule_id + 1);
# }
# state.rules[rule_id] = rule;
# }
def add_rule(
state: parse_state,
rule_id: int,
rule: std.vector[LlamaGrammarElement],
) -> None:
if state.rules.size() <= rule_id:
state.rules.resize(
rule_id + 1,
fill_value_factory=std.vector[LlamaGrammarElement],
)
state.rules[rule_id] = rule
# std::pair<uint32_t, const char *> decode_utf8(const char * src) {
# static const int lookup[] = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 4 };
# uint8_t first_byte = static_cast<uint8_t>(*src);
# uint8_t highbits = first_byte >> 4;
# int len = lookup[highbits];
# uint8_t mask = (1 << (8 - len)) - 1;
# uint32_t value = first_byte & mask;
# const char * end = src + len; // may overrun!
# const char * pos = src + 1;
# for ( ; pos < end && *pos; pos++) {
# value = (value << 6) + (static_cast<uint8_t>(*pos) & 0x3F);
# }
# return std::make_pair(value, pos);
# }
def decode_utf8(src: const_char_p) -> Tuple[int, const_char_p]:
"""Decodes a UTF-8 character from the source string."""
# Get the codepoint of the first character
value = ord(src[0])
# Move the pointer ahead one character
pos = src + 1
return value, pos
# bool is_word_char(char c) {
# return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || c == '-' || ('0' <= c && c <= '9');
# }
def is_word_char(c: str) -> bool:
return ("a" <= c <= "z") or ("A" <= c <= "Z") or c == "-" or ("0" <= c <= "9")
# std::pair<uint32_t, const char *> parse_hex(const char * src, int size) {
# const char * pos = src;
# const char * end = src + size;
# uint32_t value = 0;
# for ( ; pos < end && *pos; pos++) {
# value <<= 4;
# char c = *pos;
# if ('a' <= c && c <= 'f') {
# value += c - 'a' + 10;
# } else if ('A' <= c && c <= 'F') {
# value += c - 'A' + 10;
# } else if ('0' <= c && c <= '9') {
# value += c - '0';
# } else {
# break;
# }
# }
# if (pos != end) {
# throw std::runtime_error("expecting " + std::to_string(size) + " hex chars at " + src);
# }
# return std::make_pair(value, pos);
# }
def parse_hex(src: const_char_p, size: int) -> Tuple[int, const_char_p]:
pos = const_char_p(src) # type: const_char_p
end = src + size # type: const_char_p
value = 0 # type: int
while pos < end and pos[0]:
value <<= 4
c = pos[0] # type: str
if "a" <= c <= "f":
value += ord(c) - ord("a") + 10
elif "A" <= c <= "F":
value += ord(c) - ord("A") + 10
elif "0" <= c <= "9":
value += ord(c) - ord("0")
else:
break
pos += 1
if pos != end:
raise RuntimeError("expecting " + str(size) + " hex chars at " + str(src))
return (value, pos)
# std::pair<uint32_t, const char *> parse_char(const char * src) {
# if (*src == '\\') {
# switch (src[1]) {
# case 'x': return parse_hex(src + 2, 2);
# case 'u': return parse_hex(src + 2, 4);
# case 'U': return parse_hex(src + 2, 8);
# case 't': return std::make_pair('\t', src + 2);
# case 'r': return std::make_pair('\r', src + 2);
# case 'n': return std::make_pair('\n', src + 2);
# case '\\':
# case '"':
# case '[':
# case ']':
# return std::make_pair(src[1], src + 2);
# default:
# throw std::runtime_error(std::string("unknown escape at ") + src);
# }
# } else if (*src) {
# return decode_utf8(src);
# }
# throw std::runtime_error("unexpected end of input");
# }
def parse_char(src: const_char_p) -> Tuple[int, const_char_p]:
if src[0] == "\\":
case = src[1] # type: str
if case == "x":
return parse_hex(src + 2, 2)
elif case == "u":
return parse_hex(src + 2, 4)
elif case == "U":
return parse_hex(src + 2, 8)
elif case == "t":
return (ord("\t"), src + 2) # implicit cast
elif case == "r":
return (ord("\r"), src + 2) # implicit cast
elif case == "n":
return (ord("\n"), src + 2) # implicit cast
elif case in ("\\", '"', "[", "]"):
return (ord(case), src + 2) # implicit cast
else:
raise RuntimeError("unknown escape at " + str(src))
elif src[0]:
return decode_utf8(src)
else:
raise RuntimeError("unexpected end of input")
# const char * parse_name(const char * src) {
# const char * pos = src;
# while (is_word_char(*pos)) {
# pos++;
# }
# if (pos == src) {
# throw std::runtime_error(std::string("expecting name at ") + src);
# }
# return pos;
# }
def parse_name(src: const_char_p) -> const_char_p:
pos = const_char_p(src) # type: const_char_p
while is_word_char(pos[0]):
pos += 1
if pos == src:
raise RuntimeError("expecting name at " + str(src))
return pos
# const char * parse_space(const char * src, bool newline_ok) {
# const char * pos = src;
# while (*pos == ' ' || *pos == '\t' || *pos == '#' ||
# (newline_ok && (*pos == '\r' || *pos == '\n'))) {
# if (*pos == '#') {
# while (*pos && *pos != '\r' && *pos != '\n') {
# pos++;
# }
# } else {
# pos++;
# }
# }
# return pos;
# }
def parse_space(src: const_char_p, newline_ok: bool) -> const_char_p:
pos = const_char_p(src) # type: const_char_p
while pos[0] in (" ", "\t", "#") or (newline_ok and pos[0] in ("\r", "\n")):
if pos[0] == "#":
while pos[0] is not None and pos[0] not in ("\r", "\n"):
pos += 1
else:
pos += 1
return pos
# const char * parse_sequence(
# parse_state & state,
# const char * src,
# const std::string & rule_name,
# std::vector<llama_grammar_element> & out_elements,
# bool is_nested) {
def parse_sequence(
state: parse_state,
src: const_char_p,
rule_name: str,
out_elements: std.vector[LlamaGrammarElement],
is_nested: bool,
) -> const_char_p:
# size_t last_sym_start = out_elements.size();
# const char * pos = src;
last_sym_start = out_elements.size() # type: int
pos = const_char_p(src) # type: const_char_p
# while (*pos) {
while pos[0]:
# if (*pos == '"') { // literal string
# pos++;
# last_sym_start = out_elements.size();
# while (*pos != '"') {
# auto char_pair = parse_char(pos);
# pos = char_pair.second;
# out_elements.push_back({LLAMA_GRETYPE_CHAR, char_pair.first});
# }
# pos = parse_space(pos + 1, is_nested);
if pos[0] == '"': # literal string
pos += 1
last_sym_start = out_elements.size()
while pos[0] != '"':
char_pair = parse_char(pos) # type: Tuple[int, const_char_p]
pos = char_pair[1]
out_elements.push_back(
LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_CHAR, char_pair[0])
)
pos = parse_space(pos + 1, is_nested)
# } else if (*pos == '[') { // char range(s)
# pos++;
# enum llama_gretype start_type = LLAMA_GRETYPE_CHAR;
elif pos[0] == "[": # char range(s)
pos += 1
start_type = llama_gretype.LLAMA_GRETYPE_CHAR # type: llama_gretype
# if (*pos == '^') {
# pos++;
# start_type = LLAMA_GRETYPE_CHAR_NOT;
# }
# last_sym_start = out_elements.size();
if pos[0] == "^":
pos += 1
start_type = llama_gretype.LLAMA_GRETYPE_CHAR_NOT
last_sym_start = out_elements.size()
# while (*pos != ']') {
# auto char_pair = parse_char(pos);
# pos = char_pair.second;
# enum llama_gretype type = last_sym_start < out_elements.size()
# ? LLAMA_GRETYPE_CHAR_ALT
# : start_type;
# out_elements.push_back({type, char_pair.first});
while pos[0] != "]":
char_pair = parse_char(pos) # type: Tuple[int, const_char_p]
pos = char_pair[1]
type = (
llama_gretype.LLAMA_GRETYPE_CHAR_ALT
if last_sym_start < out_elements.size()
else start_type
) # type: llama_gretype
out_elements.push_back(LlamaGrammarElement(type, char_pair[0]))
# if (pos[0] == '-' && pos[1] != ']') {
# auto endchar_pair = parse_char(pos + 1);
# pos = endchar_pair.second;
# out_elements.push_back({LLAMA_GRETYPE_CHAR_RNG_UPPER, endchar_pair.first});
# }
# }
if pos[0] == "-" and pos[1] != "]":
endchar_pair = parse_char(pos + 1) # type: Tuple[int, const_char_p]
pos = endchar_pair[1]
out_elements.push_back(
LlamaGrammarElement(
llama_gretype.LLAMA_GRETYPE_CHAR_RNG_UPPER,
endchar_pair[0],
)
)
# pos = parse_space(pos + 1, is_nested);
pos = parse_space(pos + 1, is_nested)
# } else if (is_word_char(*pos)) { // rule reference
# const char * name_end = parse_name(pos);
# uint32_t ref_rule_id = get_symbol_id(state, pos, name_end - pos);
# pos = parse_space(name_end, is_nested);
# last_sym_start = out_elements.size();
# out_elements.push_back({LLAMA_GRETYPE_RULE_REF, ref_rule_id});
elif is_word_char(pos[0]): # rule reference
name_end = parse_name(pos) # type: const_char_p
ref_rule_id = get_symbol_id(state, pos, name_end - pos) # type: int
pos = parse_space(name_end, is_nested)
last_sym_start = out_elements.size()
out_elements.push_back(
LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_RULE_REF, ref_rule_id)
)
# } else if (*pos == '(') { // grouping
# // parse nested alternates into synthesized rule
# pos = parse_space(pos + 1, true);
# uint32_t sub_rule_id = generate_symbol_id(state, rule_name);
# pos = parse_alternates(state, pos, rule_name, sub_rule_id, true);
# last_sym_start = out_elements.size();
# // output reference to synthesized rule
# out_elements.push_back({LLAMA_GRETYPE_RULE_REF, sub_rule_id});
# if (*pos != ')') {
# throw std::runtime_error(std::string("expecting ')' at ") + pos);
# }
# pos = parse_space(pos + 1, is_nested);
elif pos[0] == "(": # grouping
# parse nested alternates into synthesized rule
pos = parse_space(pos + 1, True)
sub_rule_id = generate_symbol_id(state, rule_name) # type: int
pos = parse_alternates(state, pos, rule_name, sub_rule_id, True)
last_sym_start = out_elements.size()
# output reference to synthesized rule
out_elements.push_back(
LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_RULE_REF, sub_rule_id)
)
if pos[0] != ")":
raise RuntimeError("expecting ')' at " + str(pos))
pos = parse_space(pos + 1, is_nested)
# } else if (*pos == '*' || *pos == '+' || *pos == '?') { // repetition operator
# if (last_sym_start == out_elements.size()) {
# throw std::runtime_error(std::string("expecting preceeding item to */+/? at ") + pos);
# }
elif pos[0] in ("*", "+", "?"): # repetition operator
if last_sym_start == out_elements.size():
raise RuntimeError("expecting preceding item to */+/? at " + str(pos))
# // apply transformation to previous symbol (last_sym_start to end) according to
# // rewrite rules:
# // S* --> S' ::= S S' |
# // S+ --> S' ::= S S' | S
# // S? --> S' ::= S |
# uint32_t sub_rule_id = generate_symbol_id(state, rule_name);
# std::vector<llama_grammar_element> sub_rule;
# // add preceding symbol to generated rule
# sub_rule.insert(
# sub_rule.end(), out_elements.begin() + last_sym_start, out_elements.end());
sub_rule_id = generate_symbol_id(state, rule_name) # type: int
sub_rule = std.vector[
LlamaGrammarElement
]() # type: std.vector[LlamaGrammarElement]
sub_rule.insert(
sub_rule.end(),
out_elements.begin() + last_sym_start,
out_elements.end(),
)
# if (*pos == '*' || *pos == '+') {
# // cause generated rule to recurse
# sub_rule.push_back({LLAMA_GRETYPE_RULE_REF, sub_rule_id});
# }
# // mark start of alternate def
# sub_rule.push_back({LLAMA_GRETYPE_ALT, 0});
if pos[0] in ("*", "+"):
sub_rule.push_back(
LlamaGrammarElement(
llama_gretype.LLAMA_GRETYPE_RULE_REF, sub_rule_id
)
)
sub_rule.push_back(LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_ALT, 0))
# if (*pos == '+') {
# // add preceding symbol as alternate only for '+' (otherwise empty)
# sub_rule.insert(
# sub_rule.end(), out_elements.begin() + last_sym_start, out_elements.end());
# }
# sub_rule.push_back({LLAMA_GRETYPE_END, 0});
# add_rule(state, sub_rule_id, sub_rule);
# // in original rule, replace previous symbol with reference to generated rule
# out_elements.resize(last_sym_start);
# out_elements.push_back({LLAMA_GRETYPE_RULE_REF, sub_rule_id});
# pos = parse_space(pos + 1, is_nested);
if pos[0] == "+":
# add preceding symbol as alternate only for '+' (otherwise empty)
sub_rule.insert(
sub_rule.end(),
out_elements.begin() + last_sym_start,
out_elements.end(),
)
sub_rule.push_back(LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_END, 0))
add_rule(state, sub_rule_id, sub_rule)
# in original rule, replace previous symbol with reference to generated rule
out_elements.resize(last_sym_start)
out_elements.push_back(
LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_RULE_REF, sub_rule_id)
)
pos = parse_space(pos + 1, is_nested)
# } else {
# break;
# }
else:
break
# }
# return pos;
# }
return pos
# const char * parse_alternates(
# parse_state & state,
# const char * src,
# const std::string & rule_name,
# uint32_t rule_id,
# bool is_nested) {
# std::vector<llama_grammar_element> rule;
# const char * pos = parse_sequence(state, src, rule_name, rule, is_nested);
# while (*pos == '|') {
# rule.push_back({LLAMA_GRETYPE_ALT, 0});
# pos = parse_space(pos + 1, true);
# pos = parse_sequence(state, pos, rule_name, rule, is_nested);
# }
# rule.push_back({LLAMA_GRETYPE_END, 0});
# add_rule(state, rule_id, rule);
# return pos;
# }
def parse_alternates(
state: parse_state,
src: const_char_p,
rule_name: str,
rule_id: int,
is_nested: bool,
) -> const_char_p:
rule = std.vector() # type: std.vector[LlamaGrammarElement]
pos = parse_sequence(state, src, rule_name, rule, is_nested) # type: const_char_p
while pos[0] == "|":
rule.push_back(LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_ALT, 0))
pos = parse_space(pos + 1, True)
pos = parse_sequence(state, pos, rule_name, rule, is_nested)
rule.push_back(LlamaGrammarElement(llama_gretype.LLAMA_GRETYPE_END, 0))
add_rule(state, rule_id, rule)
return pos
# const char * parse_rule(parse_state & state, const char * src) {
# const char * name_end = parse_name(src);
# const char * pos = parse_space(name_end, false);
# size_t name_len = name_end - src;
# uint32_t rule_id = get_symbol_id(state, src, name_len);
# const std::string name(src, name_len);
# if (!(pos[0] == ':' && pos[1] == ':' && pos[2] == '=')) {
# throw std::runtime_error(std::string("expecting ::= at ") + pos);
# }
# pos = parse_space(pos + 3, true);
# pos = parse_alternates(state, pos, name, rule_id, false);
# if (*pos == '\r') {
# pos += pos[1] == '\n' ? 2 : 1;
# } else if (*pos == '\n') {
# pos++;
# } else if (*pos) {
# throw std::runtime_error(std::string("expecting newline or end at ") + pos);
# }
# return parse_space(pos, true);
# }
def parse_rule(state: parse_state, src: const_char_p) -> const_char_p:
name_end = parse_name(src) # type: const_char_p
pos = parse_space(name_end, False) # type: const_char_p
name_len = name_end - src # type: int
rule_id = get_symbol_id(state, src, name_len) # type: int
name = std.string(src, name_len) # type: str
if not (pos[0] == ":" and pos[1] == ":" and pos[2] == "="):
raise RuntimeError("expecting ::= at " + str(pos))
pos = parse_space(pos + 3, True) # type: const_char_p
pos = parse_alternates(state, pos, name, rule_id, False) # type: const_char_p
if pos[0] == "\r":
pos += 2 if pos[1] == "\n" else 1
elif pos[0] == "\n":
pos += 1
elif pos[0]:
raise RuntimeError("expecting newline or end at " + str(pos))
return parse_space(pos, True)
# parse_state parse(const char * src) {
# try {
# parse_state state;
# const char * pos = parse_space(src, true);
# while (*pos) {
# pos = parse_rule(state, pos);
# }
# return state;
# } catch (const std::exception & err) {
# fprintf(stderr, "%s: error parsing grammar: %s\n", __func__, err.what());
# return parse_state();
# }
# }
def parse(src: const_char_p) -> parse_state:
try:
state = parse_state() # type: parse_state
pos = parse_space(src, True) # type: const_char_p
while pos[0]:
pos = parse_rule(state, pos)
return state
except Exception as err:
print(f"{parse.__name__}: error parsing grammar: {err}")
return parse_state()
# void print_grammar_char(FILE * file, uint32_t c) {
# if (0x20 <= c && c <= 0x7f) {
# fprintf(file, "%c", static_cast<char>(c));
# } else {
# // cop out of encoding UTF-8
# fprintf(file, "<U+%04X>", c);
# }
# }
def print_grammar_char(file: TextIO, c: int) -> None:
if 0x20 <= c and c <= 0x7F:
file.write(chr(c))
else:
# cop out of encoding UTF-8
file.write(f"<U+{c:04X}>")
# bool is_char_element(llama_grammar_element elem) {
# switch (elem.type) {
# case LLAMA_GRETYPE_CHAR: return true;
# case LLAMA_GRETYPE_CHAR_NOT: return true;
# case LLAMA_GRETYPE_CHAR_ALT: return true;
# case LLAMA_GRETYPE_CHAR_RNG_UPPER: return true;
# default: return false;
# }
# }
def is_char_element(elem: LlamaGrammarElement) -> bool:
return elem.type in (
llama_gretype.LLAMA_GRETYPE_CHAR,
llama_gretype.LLAMA_GRETYPE_CHAR_NOT,
llama_gretype.LLAMA_GRETYPE_CHAR_ALT,
llama_gretype.LLAMA_GRETYPE_CHAR_RNG_UPPER,
)
# void print_rule(
# FILE * file,
# uint32_t rule_id,
# const std::vector<llama_grammar_element> & rule,
# const std::map<uint32_t, std::string> & symbol_id_names) {
def print_rule(
file: TextIO,
rule_id: int,
rule: std.vector[LlamaGrammarElement],
symbol_id_names: std.map[int, str],
) -> None:
# if (rule.empty() || rule.back().type != LLAMA_GRETYPE_END) {
# throw std::runtime_error(
# "malformed rule, does not end with LLAMA_GRETYPE_END: " + std::to_string(rule_id));
# }
# fprintf(file, "%s ::= ", symbol_id_names.at(rule_id).c_str());
if rule.empty() or rule.back().type != llama_gretype.LLAMA_GRETYPE_END:
raise RuntimeError(
"malformed rule, does not end with LLAMA_GRETYPE_END: " + str(rule_id)
)
print(f"{symbol_id_names.at(rule_id)} ::=", file=file, end=" ")
# for (size_t i = 0, end = rule.size() - 1; i < end; i++) {
# llama_grammar_element elem = rule[i];
# switch (elem.type) {
# case LLAMA_GRETYPE_END:
# throw std::runtime_error(
# "unexpected end of rule: " + std::to_string(rule_id) + "," +
# std::to_string(i));
# case LLAMA_GRETYPE_ALT:
# fprintf(file, "| ");
# break;
# case LLAMA_GRETYPE_RULE_REF:
# fprintf(file, "%s ", symbol_id_names.at(elem.value).c_str());
# break;
# case LLAMA_GRETYPE_CHAR:
# fprintf(file, "[");
# print_grammar_char(file, elem.value);
# break;
# case LLAMA_GRETYPE_CHAR_NOT:
# fprintf(file, "[^");
# print_grammar_char(file, elem.value);
# break;
# case LLAMA_GRETYPE_CHAR_RNG_UPPER:
# if (i == 0 || !is_char_element(rule[i - 1])) {
# throw std::runtime_error(
# "LLAMA_GRETYPE_CHAR_RNG_UPPER without preceding char: " +
# std::to_string(rule_id) + "," + std::to_string(i));
# }
# fprintf(file, "-");
# print_grammar_char(file, elem.value);
# break;
# case LLAMA_GRETYPE_CHAR_ALT:
# if (i == 0 || !is_char_element(rule[i - 1])) {
# throw std::runtime_error(
# "LLAMA_GRETYPE_CHAR_ALT without preceding char: " +
# std::to_string(rule_id) + "," + std::to_string(i));
# }
# print_grammar_char(file, elem.value);
# break;
# }
for i, elem in enumerate(rule[:-1]):
case = elem.type # type: llama_gretype
if case is llama_gretype.LLAMA_GRETYPE_END:
raise RuntimeError("unexpected end of rule: " + str(rule_id) + "," + str(i))
elif case is llama_gretype.LLAMA_GRETYPE_ALT:
print("| ", file=file, end="")
elif case is llama_gretype.LLAMA_GRETYPE_RULE_REF:
print(f"{symbol_id_names.at(elem.value)} ", file=file, end="")
elif case is llama_gretype.LLAMA_GRETYPE_CHAR:
print("[", file=file, end="")
print_grammar_char(file, elem.value)
elif case is llama_gretype.LLAMA_GRETYPE_CHAR_NOT:
print("[^", file=file, end="")
print_grammar_char(file, elem.value)
elif case is llama_gretype.LLAMA_GRETYPE_CHAR_RNG_UPPER:
if i == 0 or not is_char_element(rule[i - 1]):
raise RuntimeError(
"LLAMA_GRETYPE_CHAR_RNG_UPPER without preceding char: "
+ str(rule_id)
+ ","
+ str(i)
)
print("-", file=file, end="")
print_grammar_char(file, elem.value)
elif case is llama_gretype.LLAMA_GRETYPE_CHAR_ALT:
if i == 0 or not is_char_element(rule[i - 1]):
raise RuntimeError(
"LLAMA_GRETYPE_CHAR_ALT without preceding char: "
+ str(rule_id)
+ ","
+ str(i)
)
print_grammar_char(file, elem.value)
# if (is_char_element(elem)) {
# switch (rule[i + 1].type) {
# case LLAMA_GRETYPE_CHAR_ALT:
# case LLAMA_GRETYPE_CHAR_RNG_UPPER:
# break;
# default:
# fprintf(file, "] ");
if is_char_element(elem):
if rule[i + 1].type in (
llama_gretype.LLAMA_GRETYPE_CHAR_ALT,
llama_gretype.LLAMA_GRETYPE_CHAR_RNG_UPPER,
):
pass
else:
print("] ", file=file, end="")
# }
# }
# }
# fprintf(file, "\n");
# }
print(file=file)
# void print_grammar(FILE * file, const parse_state & state) {
# try {
# std::map<uint32_t, std::string> symbol_id_names;
# for (auto kv : state.symbol_ids) {
# symbol_id_names[kv.second] = kv.first;
# }
# for (size_t i = 0, end = state.rules.size(); i < end; i++) {
# // fprintf(file, "%zu: ", i);
# // print_rule_binary(file, state.rules[i]);
# print_rule(file, i, state.rules[i], symbol_id_names);
# // fprintf(file, "\n");
# }
# } catch (const std::exception & err) {
# fprintf(stderr, "\n%s: error printing grammar: %s\n", __func__, err.what());
# }
# }
def print_grammar(file: TextIO, state: parse_state) -> None:
try:
symbol_id_names = std.map() # type: std.map[int, str]
for kv in state.symbol_ids.items():
symbol_id_names[kv[1]] = kv[0]
for i, rule in enumerate(state.rules):
print_rule(file, i, rule, symbol_id_names)
except Exception as err:
print(
f"{print_grammar.__name__}: error printing grammar: {err}",
file=sys.stderr,
)
"""llama.cpp gbnf rules from vendor/llama.cpp/grammars"""
ARITHMETIC_GBNF = r"""
root ::= (expr "=" ws term "\n")+
expr ::= term ([-+*/] term)*
term ::= ident | num | "(" ws expr ")" ws
ident ::= [a-z] [a-z0-9_]* ws
num ::= [0-9]+ ws
ws ::= [ \t\n]*
"""
C_GBNF = r"""
root ::= (declaration)*
declaration ::= dataType identifier "(" parameter? ")" "{" statement* "}"
dataType ::= "int" ws | "float" ws | "char" ws
identifier ::= [a-zA-Z_] [a-zA-Z_0-9]*
parameter ::= dataType identifier
statement ::=
( dataType identifier ws "=" ws expression ";" ) |
( identifier ws "=" ws expression ";" ) |
( identifier ws "(" argList? ")" ";" ) |
( "return" ws expression ";" ) |
( "while" "(" condition ")" "{" statement* "}" ) |
( "for" "(" forInit ";" ws condition ";" ws forUpdate ")" "{" statement* "}" ) |
( "if" "(" condition ")" "{" statement* "}" ("else" "{" statement* "}")? ) |
( singleLineComment ) |
( multiLineComment )
forInit ::= dataType identifier ws "=" ws expression | identifier ws "=" ws expression
forUpdate ::= identifier ws "=" ws expression
condition ::= expression relationOperator expression
relationOperator ::= ("<=" | "<" | "==" | "!=" | ">=" | ">")
expression ::= term (("+" | "-") term)*
term ::= factor(("*" | "/") factor)*
factor ::= identifier | number | unaryTerm | funcCall | parenExpression
unaryTerm ::= "-" factor
funcCall ::= identifier "(" argList? ")"
parenExpression ::= "(" ws expression ws ")"
argList ::= expression ("," ws expression)*
number ::= [0-9]+
singleLineComment ::= "//" [^\n]* "\n"
multiLineComment ::= "/*" ( [^*] | ("*" [^/]) )* "*/"
ws ::= ([ \t\n]+)
"""
CHESS_GBNF = r"""
root ::= object
value ::= object | array | string | number | ("true" | "false" | "null") ws
object ::=
"{" ws (
string ":" ws value
("," ws string ":" ws value)*
)? "}" ws
array ::=
"[" ws (
value
("," ws value)*
)? "]" ws
string ::=
"\"" (
[^"\\] |
"\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F]) # escapes
)* "\"" ws
number ::= ("-"? ([0-9] | [1-9] [0-9]*)) ("." [0-9]+)? ([eE] [-+]? [0-9]+)? ws
# Optional space: by convention, applied in this grammar after literal chars when allowed
ws ::= ([ \t\n] ws)?
"""
JAPANESE_GBNF = r"""
root ::= object
value ::= object | array | string | number | ("true" | "false" | "null") ws
object ::=
"{" ws (
string ":" ws value
("," ws string ":" ws value)*
)? "}" ws
array ::=
"[" ws (
value
("," ws value)*
)? "]" ws
string ::=
"\"" (
[^"\\] |
"\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F]) # escapes
)* "\"" ws
number ::= ("-"? ([0-9] | [1-9] [0-9]*)) ("." [0-9]+)? ([eE] [-+]? [0-9]+)? ws
# Optional space: by convention, applied in this grammar after literal chars when allowed
ws ::= ([ \t\n] ws)?
"""
JSON_ARR_GBNF = r"""
# This is the same as json.gbnf but we restrict whitespaces at the end of the root array
# Useful for generating JSON arrays
root ::= arr
value ::= object | array | string | number | ("true" | "false" | "null") ws
arr ::=
"[\n" ws (
value
(",\n" ws value)*
)? "]"
object ::=
"{" ws (
string ":" ws value
("," ws string ":" ws value)*
)? "}" ws
array ::=
"[" ws (
value
("," ws value)*
)? "]" ws
string ::=
"\"" (
[^"\\\x7F\x00-\x1F] |
"\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F]) # escapes
)* "\"" ws
number ::= ("-"? ([0-9] | [1-9] [0-9]*)) ("." [0-9]+)? ([eE] [-+]? [0-9]+)? ws
# Optional space: by convention, applied in this grammar after literal chars when allowed
ws ::= ([ \t\n] ws)?
"""
JSON_GBNF = r"""
root ::= object
value ::= object | array | string | number | ("true" | "false" | "null") ws
object ::=
"{" ws (
string ":" ws value
("," ws string ":" ws value)*
)? "}" ws
array ::=
"[" ws (
value
("," ws value)*
)? "]" ws
string ::=
"\"" (
[^"\\\x7F\x00-\x1F] |
"\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F]) # escapes
)* "\"" ws
number ::= ("-"? ([0-9] | [1-9] [0-9]*)) ("." [0-9]+)? ([eE] [-+]? [0-9]+)? ws
ws ::= ([ \t\n] ws)?
"""
LIST_GBNF = r"""
root ::= item+
# Excludes various line break characters
item ::= "- " [^\r\n\x0b\x0c\x85\u2028\u2029]+ "\n"
"""
"""llama.cpp json-schema to grammar converter from vendor/llama.cpp/examples/json-schema-to-grammar.py"""
import json
import re
from typing import List, Optional
# whitespace is constrained to a single space char to prevent model "running away" in
# whitespace. Also maybe improves generation quality?
SPACE_RULE = '" "?'
INVALID_RULE_CHARS_RE = re.compile(r"[^a-zA-Z0-9-]+")
GRAMMAR_LITERAL_ESCAPE_RE = re.compile(r'[\r\n"]')
GRAMMAR_LITERAL_ESCAPES = {"\r": "\\r", "\n": "\\n", '"': '\\"'}
# whitespace is constrained to a single space char to prevent model "running away" in
# whitespace. Also maybe improves generation quality?
SPACE_RULE = '" "?'
def _build_repetition(item_rule, min_items, max_items, separator_rule=None, item_rule_is_literal=False):
if not separator_rule:
if min_items == 0 and max_items == 1:
return f'{item_rule}?'
elif min_items == 1 and max_items is None:
return f'{item_rule}+'
result = ''
if min_items > 0:
if item_rule_is_literal and separator_rule is None:
result = '"' + (item_rule[1:-1] * min_items) + '"'
else:
result = (f' {separator_rule} ' if separator_rule else ' ').join([item_rule] * min_items)
def opt_repetitions(up_to_n, prefix_with_sep=False):
'''
- n=4, no sep: '(a (a (a (a)?)?)?)?'
- n=4, sep=',', prefix: '("," a ("," a ("," a ("," a)?)?)?)?'
- n=4, sep=',', no prefix: '(a ("," a ("," a ("," a)?)?)?)?'
'''
content = f'{separator_rule} {item_rule}' if prefix_with_sep and separator_rule else item_rule
if up_to_n == 0:
return ''
elif up_to_n == 1:
return f'({content})?'
elif separator_rule and not prefix_with_sep:
return f'({content} {opt_repetitions(up_to_n - 1, prefix_with_sep=True)})?'
else:
return (f'({content} ' * up_to_n).rstrip() + (')?' * up_to_n)
if min_items > 0 and max_items != min_items:
result += ' '
if max_items is not None:
result += opt_repetitions(max_items - min_items, prefix_with_sep=min_items > 0)
else:
item_operator = f'({separator_rule + " " if separator_rule else ""}{item_rule})'
if min_items == 0 and separator_rule:
result = f'({item_rule} {item_operator}*)?'
else:
result += f'{item_operator}*'
return result
class BuiltinRule:
def __init__(self, content: str, deps: list = None):
self.content = content
self.deps = deps or []
_up_to_15_digits = _build_repetition('[0-9]', 0, 15)
PRIMITIVE_RULES = {
'boolean' : BuiltinRule('("true" | "false") space', []),
'decimal-part' : BuiltinRule('[0-9] ' + _up_to_15_digits, []),
'integral-part': BuiltinRule('[0-9] | [1-9] ' + _up_to_15_digits, []),
'number' : BuiltinRule('("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space', ['integral-part', 'decimal-part']),
'integer' : BuiltinRule('("-"? integral-part) space', ['integral-part']),
'value' : BuiltinRule('object | array | string | number | boolean | null', ['object', 'array', 'string', 'number', 'boolean', 'null']),
'object' : BuiltinRule('"{" space ( string ":" space value ("," space string ":" space value)* )? "}" space', ['string', 'value']),
'array' : BuiltinRule('"[" space ( value ("," space value)* )? "]" space', ['value']),
'uuid' : BuiltinRule(r'"\"" ' + ' "-" '.join('[0-9a-fA-F]' * n for n in [8, 4, 4, 4, 12]) + r' "\"" space', []),
'char' : BuiltinRule(r'[^"\\] | "\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F])', []),
'string' : BuiltinRule(r'"\"" char* "\"" space', ['char']),
'null' : BuiltinRule('"null" space', []),
}
# TODO: support "uri", "email" string formats
STRING_FORMAT_RULES = {
'date' : BuiltinRule('[0-9] [0-9] [0-9] [0-9] "-" ( "0" [1-9] | "1" [0-2] ) "-" ( \"0\" [1-9] | [1-2] [0-9] | "3" [0-1] )', []),
'time' : BuiltinRule('([01] [0-9] | "2" [0-3]) ":" [0-5] [0-9] ":" [0-5] [0-9] ( "." [0-9] [0-9] [0-9] )? ( "Z" | ( "+" | "-" ) ( [01] [0-9] | "2" [0-3] ) ":" [0-5] [0-9] )', []),
'date-time' : BuiltinRule('date "T" time', ['date', 'time']),
'date-string' : BuiltinRule('"\\"" date "\\"" space', ['date']),
'time-string' : BuiltinRule('"\\"" time "\\"" space', ['time']),
'date-time-string': BuiltinRule('"\\"" date-time "\\"" space', ['date-time']),
}
DOTALL = '[\\U00000000-\\U0010FFFF]'
DOT = '[^\\x0A\\x0D]'
RESERVED_NAMES = set(["root", "dot", *PRIMITIVE_RULES.keys(), *STRING_FORMAT_RULES.keys()])
NON_LITERAL_SET = set('|.()[]{}*+?')
ESCAPED_IN_REGEXPS_BUT_NOT_IN_LITERALS = set('[]()|{}*+?')
class SchemaConverter:
def __init__(self, *, prop_order, allow_fetch, dotall, raw_pattern):
self._prop_order = prop_order
self._allow_fetch = allow_fetch
self._dotall = dotall
self._raw_pattern = raw_pattern
self._rules = {
'space': SPACE_RULE,
}
self._refs = {}
self._refs_being_resolved = set()
def _format_literal(self, literal):
escaped = GRAMMAR_LITERAL_ESCAPE_RE.sub(
lambda m: GRAMMAR_LITERAL_ESCAPES.get(m.group(0)), literal
)
return f'"{escaped}"'
def not_literal(self, literal: str, dotall: bool = True, maybe_escaped_underscores = False) -> str:
'''
not_literal('a') -> '[^a]'
not_literal('abc') -> '([^a] | "a" ([^b] | "b" ([^c])?)?)?'
'''
assert len(literal) > 0, 'Empty literal not supported'
def recurse(i: int):
c = literal[i]
if maybe_escaped_underscores and c == '_':
yield f'[^{c}\\\\]'
yield ' | '
yield f'"\\\\"? "{c}"'
else:
yield f'[^{c}]'
if i < len(literal) - 1:
yield ' | '
yield self._format_literal(c)
yield ' ('
yield from recurse(i + 1)
yield ')?'
return ''.join(('(', *recurse(0), ')'))
def _add_rule(self, name, rule):
esc_name = INVALID_RULE_CHARS_RE.sub('-', name)
if esc_name not in self._rules or self._rules[esc_name] == rule:
key = esc_name
else:
i = 0
while f'{esc_name}{i}' in self._rules and self._rules[f'{esc_name}{i}'] != rule:
i += 1
key = f'{esc_name}{i}'
self._rules[key] = rule
return key
def resolve_refs(self, schema: dict, url: str):
'''
Resolves all $ref fields in the given schema, fetching any remote schemas,
replacing $ref with absolute reference URL and populating self._refs with the
respective referenced (sub)schema dictionaries.
'''
def visit(n: dict):
if isinstance(n, list):
return [visit(x) for x in n]
elif isinstance(n, dict):
ref = n.get('$ref')
if ref is not None and ref not in self._refs:
if ref.startswith('https://'):
assert self._allow_fetch, 'Fetching remote schemas is not allowed (use --allow-fetch for force)'
import requests
frag_split = ref.split('#')
base_url = frag_split[0]
target = self._refs.get(base_url)
if target is None:
target = self.resolve_refs(requests.get(ref).json(), base_url)
self._refs[base_url] = target
if len(frag_split) == 1 or frag_split[-1] == '':
return target
elif ref.startswith('#/'):
target = schema
ref = f'{url}{ref}'
n['$ref'] = ref
else:
raise ValueError(f'Unsupported ref {ref}')
for sel in ref.split('#')[-1].split('/')[1:]:
assert target is not None and sel in target, f'Error resolving ref {ref}: {sel} not in {target}'
target = target[sel]
self._refs[ref] = target
else:
for v in n.values():
visit(v)
return n
return visit(schema)
def _generate_union_rule(self, name, alt_schemas):
return ' | '.join((
self.visit(alt_schema, f'{name}{"-" if name else "alternative-"}{i}')
for i, alt_schema in enumerate(alt_schemas)
))
def _visit_pattern(self, pattern, name):
'''
Transforms a regular expression pattern into a GBNF rule.
Input: https://json-schema.org/understanding-json-schema/reference/regular_expressions
Output: https://github.com/ggerganov/llama.cpp/blob/master/grammars/README.md
Unsupported features: negative/positive lookaheads, greedy/non-greedy modifiers.
Mostly a 1:1 translation, except for {x} / {x,} / {x,y} quantifiers for which
we define sub-rules to keep the output lean.
'''
assert pattern.startswith('^') and pattern.endswith('$'), 'Pattern must start with "^" and end with "$"'
pattern = pattern[1:-1]
sub_rule_ids = {}
i = 0
length = len(pattern)
def to_rule(s: Tuple[str, bool]) -> str:
(txt, is_literal) = s
return "\"" + txt + "\"" if is_literal else txt
def transform() -> Tuple[str, bool]:
'''
Parse a unit at index i (advancing it), and return its string representation + whether it's a literal.
'''
nonlocal i
nonlocal pattern
nonlocal sub_rule_ids
start = i
# For each component of this sequence, store its string representation and whether it's a literal.
# We only need a flat structure here to apply repetition operators to the last item, and
# to merge literals at the and (we're parsing grouped ( sequences ) recursively and don't treat '|' specially
# (GBNF's syntax is luckily very close to regular expressions!)
seq: list[Tuple[str, bool]] = []
def get_dot():
if self._dotall:
rule = DOTALL
else:
# Accept any character... except \n and \r line break chars (\x0A and \xOD)
rule = DOT
return self._add_rule(f'dot', rule)
def join_seq():
nonlocal seq
ret = []
for is_literal, g in groupby(seq, lambda x: x[1]):
if is_literal:
ret.append((''.join(x[0] for x in g), True))
else:
ret.extend(g)
if len(ret) == 1:
return ret[0]
return (' '.join(to_rule(x) for x in seq), False)
while i < length:
c = pattern[i]
if c == '.':
seq.append((get_dot(), False))
i += 1
elif c == '(':
i += 1
if i < length:
assert pattern[i] != '?', f'Unsupported pattern syntax "{pattern[i]}" at index {i} of /{pattern}/'
seq.append((f'({to_rule(transform())})', False))
elif c == ')':
i += 1
assert start > 0 and pattern[start-1] == '(', f'Unbalanced parentheses; start = {start}, i = {i}, pattern = {pattern}'
return join_seq()
elif c == '[':
square_brackets = c
i += 1
while i < length and pattern[i] != ']':
if pattern[i] == '\\':
square_brackets += pattern[i:i+2]
i += 2
else:
square_brackets += pattern[i]
i += 1
assert i < length, f'Unbalanced square brackets; start = {start}, i = {i}, pattern = {pattern}'
square_brackets += ']'
i += 1
seq.append((square_brackets, False))
elif c == '|':
seq.append(('|', False))
i += 1
elif c in ('*', '+', '?'):
seq[-1] = (to_rule(seq[-1]) + c, False)
i += 1
elif c == '{':
curly_brackets = c
i += 1
while i < length and pattern[i] != '}':
curly_brackets += pattern[i]
i += 1
assert i < length, f'Unbalanced curly brackets; start = {start}, i = {i}, pattern = {pattern}'
curly_brackets += '}'
i += 1
nums = [s.strip() for s in curly_brackets[1:-1].split(',')]
min_times = 0
max_times = None
try:
if len(nums) == 1:
min_times = int(nums[0])
max_times = min_times
else:
assert len(nums) == 2
min_times = int(nums[0]) if nums[0] else 0
max_times = int(nums[1]) if nums[1] else None
except ValueError:
raise ValueError(f'Invalid quantifier {curly_brackets} in /{pattern}/')
(sub, sub_is_literal) = seq[-1]
if not sub_is_literal:
id = sub_rule_ids.get(sub)
if id is None:
id = self._add_rule(f'{name}-{len(sub_rule_ids) + 1}', sub)
sub_rule_ids[sub] = id
sub = id
seq[-1] = (_build_repetition(f'"{sub}"' if sub_is_literal else sub, min_times, max_times, item_rule_is_literal=sub_is_literal), False)
else:
literal = ''
while i < length:
if pattern[i] == '\\' and i < length - 1:
next = pattern[i + 1]
if next in ESCAPED_IN_REGEXPS_BUT_NOT_IN_LITERALS:
i += 1
literal += pattern[i]
i += 1
else:
literal += pattern[i:i+2]
i += 2
elif pattern[i] == '"' and not self._raw_pattern:
literal += '\\"'
i += 1
elif pattern[i] not in NON_LITERAL_SET and \
(i == length - 1 or literal == '' or pattern[i+1] == '.' or pattern[i+1] not in NON_LITERAL_SET):
literal += pattern[i]
i += 1
else:
break
if literal:
seq.append((literal, True))
return join_seq()
return self._add_rule(
name,
to_rule(transform()) if self._raw_pattern \
else "\"\\\"\" " + to_rule(transform()) + " \"\\\"\" space")
def _resolve_ref(self, ref):
ref_name = ref.split('/')[-1]
if ref_name not in self._rules and ref not in self._refs_being_resolved:
self._refs_being_resolved.add(ref)
resolved = self._refs[ref]
ref_name = self.visit(resolved, ref_name)
self._refs_being_resolved.remove(ref)
return ref_name
def _generate_constant_rule(self, value):
return self._format_literal(json.dumps(value))
def visit(self, schema, name):
schema_type = schema.get('type')
schema_format = schema.get('format')
rule_name = name + '-' if name in RESERVED_NAMES else name or 'root'
if (ref := schema.get('$ref')) is not None:
return self._add_rule(rule_name, self._resolve_ref(ref))
elif 'oneOf' in schema or 'anyOf' in schema:
return self._add_rule(rule_name, self._generate_union_rule(name, schema.get('oneOf') or schema['anyOf']))
elif isinstance(schema_type, list):
return self._add_rule(rule_name, self._generate_union_rule(name, [{'type': t} for t in schema_type]))
elif 'const' in schema:
return self._add_rule(rule_name, self._generate_constant_rule(schema['const']))
elif 'enum' in schema:
rule = ' | '.join((self._generate_constant_rule(v) for v in schema['enum']))
return self._add_rule(rule_name, rule)
elif schema_type in (None, 'object') and \
('properties' in schema or \
('additionalProperties' in schema and schema['additionalProperties'] is not True)):
required = set(schema.get('required', []))
properties = list(schema.get('properties', {}).items())
return self._add_rule(rule_name, self._build_object_rule(properties, required, name, schema.get('additionalProperties')))
elif schema_type in (None, 'object') and 'allOf' in schema:
required = set()
properties = []
hybrid_name = name
def add_component(comp_schema, is_required):
if (ref := comp_schema.get('$ref')) is not None:
comp_schema = self._refs[ref]
if 'properties' in comp_schema:
for prop_name, prop_schema in comp_schema['properties'].items():
properties.append((prop_name, prop_schema))
if is_required:
required.add(prop_name)
for t in schema['allOf']:
if 'anyOf' in t:
for tt in t['anyOf']:
add_component(tt, is_required=False)
else:
add_component(t, is_required=True)
return self._add_rule(rule_name, self._build_object_rule(properties, required, hybrid_name, additional_properties=[]))
elif schema_type in (None, 'array') and ('items' in schema or 'prefixItems' in schema):
items = schema.get('items') or schema['prefixItems']
if isinstance(items, list):
return self._add_rule(
rule_name,
'"[" space ' +
' "," space '.join(
self.visit(item, f'{name}{"-" if name else ""}tuple-{i}')
for i, item in enumerate(items)) +
' "]" space')
else:
item_rule_name = self.visit(items, f'{name}{"-" if name else ""}item')
min_items = schema.get("minItems", 0)
max_items = schema.get("maxItems")
return self._add_rule(rule_name, '"[" space ' + _build_repetition(item_rule_name, min_items, max_items, separator_rule='"," space') + ' "]" space')
elif schema_type in (None, 'string') and 'pattern' in schema:
return self._visit_pattern(schema['pattern'], rule_name)
elif schema_type in (None, 'string') and re.match(r'^uuid[1-5]?$', schema_format or ''):
return self._add_primitive(
'root' if rule_name == 'root' else schema_format,
PRIMITIVE_RULES['uuid']
)
elif schema_type in (None, 'string') and f'{schema_format}-string' in STRING_FORMAT_RULES:
prim_name = f'{schema_format}-string'
return self._add_rule(rule_name, self._add_primitive(prim_name, STRING_FORMAT_RULES[prim_name]))
elif schema_type == 'string' and ('minLength' in schema or 'maxLength' in schema):
char_rule = self._add_primitive('char', PRIMITIVE_RULES['char'])
min_len = schema.get('minLength', 0)
max_len = schema.get('maxLength')
return self._add_rule(rule_name, r'"\"" ' + _build_repetition(char_rule, min_len, max_len) + r' "\"" space')
elif (schema_type == 'object') or (len(schema) == 0):
return self._add_rule(rule_name, self._add_primitive('object', PRIMITIVE_RULES['object']))
else:
assert schema_type in PRIMITIVE_RULES, f'Unrecognized schema: {schema}'
# TODO: support minimum, maximum, exclusiveMinimum, exclusiveMaximum at least for zero
return self._add_primitive('root' if rule_name == 'root' else schema_type, PRIMITIVE_RULES[schema_type])
def _add_primitive(self, name: str, rule: BuiltinRule):
n = self._add_rule(name, rule.content)
for dep in rule.deps:
dep_rule = PRIMITIVE_RULES.get(dep) or STRING_FORMAT_RULES.get(dep)
assert dep_rule, f'Rule {dep} not known'
if dep not in self._rules:
self._add_primitive(dep, dep_rule)
return n
def _build_object_rule(self, properties: List[Tuple[str, Any]], required: Set[str], name: str, additional_properties: Union[bool, Any]):
prop_order = self._prop_order
# sort by position in prop_order (if specified) then by original order
sorted_props = [kv[0] for _, kv in sorted(enumerate(properties), key=lambda ikv: (prop_order.get(ikv[1][0], len(prop_order)), ikv[0]))]
prop_kv_rule_names = {}
for prop_name, prop_schema in properties:
prop_rule_name = self.visit(prop_schema, f'{name}{"-" if name else ""}{prop_name}')
prop_kv_rule_names[prop_name] = self._add_rule(
f'{name}{"-" if name else ""}{prop_name}-kv',
fr'{self._format_literal(json.dumps(prop_name))} space ":" space {prop_rule_name}'
)
required_props = [k for k in sorted_props if k in required]
optional_props = [k for k in sorted_props if k not in required]
if additional_properties == True or isinstance(additional_properties, dict):
sub_name = f'{name}{"-" if name else ""}additional'
value_rule = self.visit({} if additional_properties == True else additional_properties, f'{sub_name}-value')
prop_kv_rule_names["*"] = self._add_rule(
f'{sub_name}-kv',
self._add_primitive('string', PRIMITIVE_RULES['string']) + f' ":" space {value_rule}'
)
optional_props.append("*")
rule = '"{" space '
rule += ' "," space '.join(prop_kv_rule_names[k] for k in required_props)
if optional_props:
rule += ' ('
if required_props:
rule += ' "," space ( '
def get_recursive_refs(ks, first_is_optional):
[k, *rest] = ks
kv_rule_name = prop_kv_rule_names[k]
if k == '*':
res = self._add_rule(
f'{name}{"-" if name else ""}additional-kvs',
f'{kv_rule_name} ( "," space ' + kv_rule_name + ' )*'
)
elif first_is_optional:
res = f'( "," space {kv_rule_name} )?'
else:
res = kv_rule_name
if len(rest) > 0:
res += ' ' + self._add_rule(
f'{name}{"-" if name else ""}{k}-rest',
get_recursive_refs(rest, first_is_optional=True)
)
return res
rule += ' | '.join(
get_recursive_refs(optional_props[i:], first_is_optional=False)
for i in range(len(optional_props))
)
if required_props:
rule += ' )'
rule += ' )?'
rule += ' "}" space'
return rule
def format_grammar(self):
return '\n'.join(
f'{name} ::= {rule}'
for name, rule in sorted(self._rules.items(), key=lambda kv: kv[0])
)
def json_schema_to_gbnf(schema: str, prop_order: Optional[List[str]] = None):
prop_order = prop_order or []
schema = json.loads(schema)
prop_order = {name: idx for idx, name in enumerate(prop_order)}
converter = SchemaConverter(prop_order=prop_order, allow_fetch=False, dotall=False, raw_pattern=False)
schema = converter.resolve_refs(schema, "stdin")
converter.visit(schema, "")
return converter.format_grammar()