Adding Support for Literal types

[Dakantz]

I have added the support as a a simple rule extension, currently tested for

• str
• enum
• int
  literals.

from llama_cpp_agent.gbnf_grammar_generator.gbnf_grammar_from_pydantic_models import (
    generate_gbnf_grammar_from_pydantic_models,
)
from pydantic import BaseModel, Field
from typing import List, Optional, Dict, Any, Literal
from enum import Enum

class TestEnum(str, Enum):
    TEST = "test"
    TARGET = "target"
class TestType(BaseModel):
    type: Literal["test"]
    name: str


class TargetType(BaseModel):
    type: Literal["target"]
    other: str


class CombinerType(BaseModel):
    combined_type: list[TestType | TargetType]
    enum_literal: Literal[TestEnum.TEST]
    int_literal: Literal[1,5]

grammar = generate_gbnf_grammar_from_pydantic_models(
    [CombinerType],
)
print(grammar)