mustache.py — langchain Source File

Source Code

"""Adapted from https://github.com/noahmorrison/chevron.

MIT License.
"""

from __future__ import annotations

import logging
from collections.abc import Iterator, Mapping, Sequence
from types import MappingProxyType
from typing import (
    TYPE_CHECKING,
    Any,
    Literal,
    cast,
)

if TYPE_CHECKING:
    from typing import TypeAlias

logger = logging.getLogger(__name__)


Scopes: TypeAlias = list[Literal[False, 0] | Mapping[str, Any]]


# Globals
_CURRENT_LINE = 1
_LAST_TAG_LINE = None


class ChevronError(SyntaxError):
    """Custom exception for Chevron errors."""


#
# Helper functions
#


def grab_literal(template: str, l_del: str) -> tuple[str, str]:
    """Parse a literal from the template.

    Args:
        template: The template to parse.
        l_del: The left delimiter.

    Returns:
        The literal and the template.
    """
    global _CURRENT_LINE

    try:
        # Look for the next tag and move the template to it
        literal, template = template.split(l_del, 1)
        _CURRENT_LINE += literal.count("\n")

    # There are no more tags in the template?
    except ValueError:
        # Then the rest of the template is a literal
// ... (645 more lines)