Class ImportParser

Lib/_pyrepl/_module_completer.py:304–449

Parses incomplete import statements that are suitable for autocomplete suggestions. Examples: - import foo -> Result(from_name=None, name='foo') - import foo. -> Result(from_name=None, name='foo.') - from foo -> Result(from_name='foo'

class ImportParser:
    """
    Parses incomplete import statements that are
    suitable for autocomplete suggestions.

    Examples:
        - import foo          -> Result(from_name=None, name='foo')
        - import foo.         -> Result(from_name=None, name='foo.')
        - from foo            -> Result(from_name='foo', name=None)
        - from foo import bar -> Result(from_name='foo', name='bar')
        - from .foo import (  -> Result(from_name='.foo', name='')

    Note that the parser works in reverse order, starting from the
    last token in the input string. This makes the parser more robust
    when parsing multiple statements.
    """
    _ignored_tokens = {
        token.INDENT, token.DEDENT, token.COMMENT,
        token.NL, token.NEWLINE, token.ENDMARKER
    }
    _keywords = {'import', 'from', 'as'}

    def __init__(self, code: str) -> None:
        self.code = code
        tokens = []
        try:
            for t in tokenize.generate_tokens(StringIO(code).readline):
                if t.type not in self._ignored_tokens:
                    tokens.append(t)
        except tokenize.TokenError as e:
            if 'unexpected EOF' not in str(e):
                # unexpected EOF is fine, since we're parsing an
                # incomplete statement, but other errors are not
                # because we may not have all the tokens so it's
                # safer to bail out
                tokens = []
        except SyntaxError:
            tokens = []
        self.tokens = TokenQueue(tokens[::-1])

    def parse(self) -> tuple[str | None, str | None] | None:
        if not (res := self._parse()):
            return None
        return res.from_name, res.name

    def _parse(self) -> Result | None:
        with self.tokens.save_state():
            return self.parse_from_import()
        with self.tokens.save_state():
            return self.parse_import()

    def parse_import(self) -> Result:
        if self.code.rstrip().endswith('import') and self.code.endswith(' '):
            return Result(name='')
        if self.tokens.peek_string(','):
            name = ''
        else:
            if self.code.endswith(' '):