82 lines
2.3 KiB
Python
82 lines
2.3 KiB
Python
"""
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Base classes for prompt_toolkit lexers.
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"""
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from abc import ABCMeta, abstractmethod
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from typing import Callable, Hashable, Optional
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from prompt_toolkit.document import Document
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from prompt_toolkit.formatted_text.base import StyleAndTextTuples
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__all__ = [
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"Lexer",
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"SimpleLexer",
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"DynamicLexer",
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]
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class Lexer(metaclass=ABCMeta):
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"""
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Base class for all lexers.
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"""
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@abstractmethod
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def lex_document(self, document: Document) -> Callable[[int], StyleAndTextTuples]:
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"""
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Takes a :class:`~prompt_toolkit.document.Document` and returns a
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callable that takes a line number and returns a list of
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``(style_str, text)`` tuples for that line.
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XXX: Note that in the past, this was supposed to return a list
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of ``(Token, text)`` tuples, just like a Pygments lexer.
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"""
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def invalidation_hash(self) -> Hashable:
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"""
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When this changes, `lex_document` could give a different output.
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(Only used for `DynamicLexer`.)
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"""
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return id(self)
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class SimpleLexer(Lexer):
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"""
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Lexer that doesn't do any tokenizing and returns the whole input as one
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token.
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:param style: The style string for this lexer.
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"""
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def __init__(self, style: str = "") -> None:
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self.style = style
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def lex_document(self, document: Document) -> Callable[[int], StyleAndTextTuples]:
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lines = document.lines
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def get_line(lineno: int) -> StyleAndTextTuples:
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" Return the tokens for the given line. "
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try:
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return [(self.style, lines[lineno])]
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except IndexError:
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return []
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return get_line
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class DynamicLexer(Lexer):
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"""
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Lexer class that can dynamically returns any Lexer.
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:param get_lexer: Callable that returns a :class:`.Lexer` instance.
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"""
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def __init__(self, get_lexer: Callable[[], Optional[Lexer]]) -> None:
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self.get_lexer = get_lexer
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self._dummy = SimpleLexer()
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def lex_document(self, document: Document) -> Callable[[int], StyleAndTextTuples]:
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lexer = self.get_lexer() or self._dummy
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return lexer.lex_document(document)
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def invalidation_hash(self) -> Hashable:
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lexer = self.get_lexer() or self._dummy
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return id(lexer)
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