parsers.py 文件源码

def lit(literal: Sequence[Input], *literals: Sequence[Sequence[Input]]) -> Parser:
    """Match a literal sequence.

    In the `TextParsers`` context, this matches the literal string
    provided. In the ``GeneralParsers`` context, this matches a sequence of
    input.

    If multiple literals are provided, they are treated as alternatives. e.g.
    ``lit('+', '-')`` is the same as ``lit('+') | lit('-')``.

    Args:
        literal: A literal to match
        *literals: Alternative literals to match

    Returns:
        A ``LiteralParser`` in the ``GeneralContext``, a ``LiteralStringParser``
        in the ``TextParsers`` context, and an ``AlternativeParser`` if multiple
        arguments are provided.
    """
    if len(literals) > 0:
        return AlternativeParser(options.handle_literal(literal), *map(options.handle_literal, literals))
    else:
        return options.handle_literal(literal)