srt/function_call/json_array_parser.py

from typing import List

from sglang.srt.entrypoints.openai.protocol import Tool
from sglang.srt.function_call.base_format_detector import BaseFormatDetector
from sglang.srt.function_call.core_types import StreamingParseResult


class JsonArrayParser(BaseFormatDetector):
    """
    Parser for JSON array tool calls when JSON schema constraints are active.

    This parser is used when tool_choice="required" or a specific tool is named,
    bypassing model-specific parsers in favor of direct JSON array parsing.
    """

    def __init__(self):
        super().__init__()
        # Configure for JSON array parsing
        self.bot_token = "["
        self.eot_token = "]"
        self.tool_call_separator = ","

    def has_tool_call(self, text: str) -> bool:
        """
        Check if the given text contains a JSON tool call (array or single object).
        """
        return "[" in text or "{" in text

    def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
        """
        Parse JSON tool calls using the base class implementation.
        """
        raise NotImplementedError(
            "Detect and parse not supported for JSON schema constraints."
        )

    def build_ebnf(self, tools: List[Tool]) -> str:
        """
        Build an EBNF grammar for constrained generation.
        This is not used for JSON schema constraints as they are handled
        by the constraint backends directly.
        """
        raise NotImplementedError(
            "EBNF generation is not supported for JSON schema constraints."
        )

    def parse_streaming_increment(
        self, new_text: str, tools: List[Tool]
    ) -> StreamingParseResult:
        """
        Streaming incremental parsing with tool validation.
        """
        return super().parse_streaming_increment(new_text, tools)

    def structure_info(self) -> callable:
        """
        Return a function that creates StructureInfo for constrained generation.
        This is not used for JSON schema constraints as they are handled
        by the constraint backends directly.
        """
        raise NotImplementedError("structure_info not used for JSON schema constraints")