214 lines
7.5 KiB
Python
214 lines
7.5 KiB
Python
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from __future__ import annotations
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import re
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from typing import Callable, Iterable, NamedTuple
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from prompt_toolkit.document import Document
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from prompt_toolkit.filters import FilterOrBool, to_filter
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from prompt_toolkit.formatted_text import AnyFormattedText, StyleAndTextTuples
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from .base import CompleteEvent, Completer, Completion
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from .word_completer import WordCompleter
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__all__ = [
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"FuzzyCompleter",
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"FuzzyWordCompleter",
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]
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class FuzzyCompleter(Completer):
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"""
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Fuzzy completion.
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This wraps any other completer and turns it into a fuzzy completer.
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If the list of words is: ["leopard" , "gorilla", "dinosaur", "cat", "bee"]
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Then trying to complete "oar" would yield "leopard" and "dinosaur", but not
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the others, because they match the regular expression 'o.*a.*r'.
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Similar, in another application "djm" could expand to "django_migrations".
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The results are sorted by relevance, which is defined as the start position
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and the length of the match.
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Notice that this is not really a tool to work around spelling mistakes,
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like what would be possible with difflib. The purpose is rather to have a
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quicker or more intuitive way to filter the given completions, especially
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when many completions have a common prefix.
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Fuzzy algorithm is based on this post:
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https://blog.amjith.com/fuzzyfinder-in-10-lines-of-python
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:param completer: A :class:`~.Completer` instance.
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:param WORD: When True, use WORD characters.
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:param pattern: Regex pattern which selects the characters before the
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cursor that are considered for the fuzzy matching.
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:param enable_fuzzy: (bool or `Filter`) Enabled the fuzzy behavior. For
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easily turning fuzzyness on or off according to a certain condition.
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"""
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def __init__(
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self,
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completer: Completer,
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WORD: bool = False,
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pattern: str | None = None,
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enable_fuzzy: FilterOrBool = True,
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) -> None:
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assert pattern is None or pattern.startswith("^")
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self.completer = completer
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self.pattern = pattern
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self.WORD = WORD
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self.pattern = pattern
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self.enable_fuzzy = to_filter(enable_fuzzy)
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def get_completions(
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self, document: Document, complete_event: CompleteEvent
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) -> Iterable[Completion]:
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if self.enable_fuzzy():
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return self._get_fuzzy_completions(document, complete_event)
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else:
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return self.completer.get_completions(document, complete_event)
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def _get_pattern(self) -> str:
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if self.pattern:
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return self.pattern
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if self.WORD:
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return r"[^\s]+"
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return "^[a-zA-Z0-9_]*"
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def _get_fuzzy_completions(
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self, document: Document, complete_event: CompleteEvent
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) -> Iterable[Completion]:
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word_before_cursor = document.get_word_before_cursor(
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pattern=re.compile(self._get_pattern())
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)
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# Get completions
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document2 = Document(
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text=document.text[: document.cursor_position - len(word_before_cursor)],
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cursor_position=document.cursor_position - len(word_before_cursor),
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)
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inner_completions = list(
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self.completer.get_completions(document2, complete_event)
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)
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fuzzy_matches: list[_FuzzyMatch] = []
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if word_before_cursor == "":
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# If word before the cursor is an empty string, consider all
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# completions, without filtering everything with an empty regex
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# pattern.
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fuzzy_matches = [_FuzzyMatch(0, 0, compl) for compl in inner_completions]
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else:
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pat = ".*?".join(map(re.escape, word_before_cursor))
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pat = f"(?=({pat}))" # lookahead regex to manage overlapping matches
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regex = re.compile(pat, re.IGNORECASE)
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for compl in inner_completions:
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matches = list(regex.finditer(compl.text))
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if matches:
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# Prefer the match, closest to the left, then shortest.
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best = min(matches, key=lambda m: (m.start(), len(m.group(1))))
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fuzzy_matches.append(
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_FuzzyMatch(len(best.group(1)), best.start(), compl)
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)
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def sort_key(fuzzy_match: _FuzzyMatch) -> tuple[int, int]:
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"Sort by start position, then by the length of the match."
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return fuzzy_match.start_pos, fuzzy_match.match_length
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fuzzy_matches = sorted(fuzzy_matches, key=sort_key)
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for match in fuzzy_matches:
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# Include these completions, but set the correct `display`
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# attribute and `start_position`.
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yield Completion(
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text=match.completion.text,
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start_position=match.completion.start_position
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- len(word_before_cursor),
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# We access to private `_display_meta` attribute, because that one is lazy.
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display_meta=match.completion._display_meta,
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display=self._get_display(match, word_before_cursor),
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style=match.completion.style,
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)
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def _get_display(
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self, fuzzy_match: _FuzzyMatch, word_before_cursor: str
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) -> AnyFormattedText:
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"""
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Generate formatted text for the display label.
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"""
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def get_display() -> AnyFormattedText:
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m = fuzzy_match
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word = m.completion.text
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if m.match_length == 0:
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# No highlighting when we have zero length matches (no input text).
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# In this case, use the original display text (which can include
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# additional styling or characters).
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return m.completion.display
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result: StyleAndTextTuples = []
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# Text before match.
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result.append(("class:fuzzymatch.outside", word[: m.start_pos]))
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# The match itself.
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characters = list(word_before_cursor)
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for c in word[m.start_pos : m.start_pos + m.match_length]:
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classname = "class:fuzzymatch.inside"
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if characters and c.lower() == characters[0].lower():
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classname += ".character"
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del characters[0]
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result.append((classname, c))
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# Text after match.
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result.append(
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("class:fuzzymatch.outside", word[m.start_pos + m.match_length :])
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)
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return result
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return get_display()
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class FuzzyWordCompleter(Completer):
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"""
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Fuzzy completion on a list of words.
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(This is basically a `WordCompleter` wrapped in a `FuzzyCompleter`.)
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:param words: List of words or callable that returns a list of words.
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:param meta_dict: Optional dict mapping words to their meta-information.
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:param WORD: When True, use WORD characters.
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"""
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def __init__(
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self,
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words: list[str] | Callable[[], list[str]],
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meta_dict: dict[str, str] | None = None,
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WORD: bool = False,
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) -> None:
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self.words = words
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self.meta_dict = meta_dict or {}
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self.WORD = WORD
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self.word_completer = WordCompleter(
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words=self.words, WORD=self.WORD, meta_dict=self.meta_dict
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)
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self.fuzzy_completer = FuzzyCompleter(self.word_completer, WORD=self.WORD)
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def get_completions(
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self, document: Document, complete_event: CompleteEvent
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) -> Iterable[Completion]:
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return self.fuzzy_completer.get_completions(document, complete_event)
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class _FuzzyMatch(NamedTuple):
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match_length: int
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start_pos: int
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completion: Completion
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