Python TokenParser.require_existing_valid_head_token Examples

Example #1

File: token_stream_parsing.py Project: emilkarlen/exactly

def parse_mandatory_choice_with_default(parser: TokenParser,
                                        syntax_element_name: str,
                                        choices: Iterable[TokenSyntaxSetup[PARSE_RESULT]],
                                        default: ParserFromTokenParser) -> PARSE_RESULT:
    parser.require_existing_valid_head_token(syntax_element_name)
    for syntax_setup in choices:
        if syntax_setup.matcher.matches(parser.head):
            parser.consume_head()
            return syntax_setup.parser_after_token(parser)
    return default(parser)

Example #2

def parse_mandatory_choice(
    token_parser: TokenParser,
    syntax_element: str,
    choices: Sequence[TokenSyntaxSetup[PARSE_RESULT]],
) -> PARSE_RESULT:
    token_parser.require_existing_valid_head_token(syntax_element)
    for syntax_setup in choices:
        if syntax_setup.matcher.matches(token_parser.head):
            token_parser.consume_head()
            return syntax_setup.parser_after_token(token_parser)
    return token_parser.report_missing(syntax_element)

Example #3

def parse_mandatory_choice_with_default(
    token_parser: TokenParser,
    syntax_element: str,
    choices: Sequence[TokenSyntaxSetup[PARSE_RESULT]],
    default: Callable[[TokenParser], PARSE_RESULT],
) -> PARSE_RESULT:
    token_parser.require_existing_valid_head_token(syntax_element)
    for syntax_setup in choices:
        if syntax_setup.matcher.matches(token_parser.head):
            token_parser.consume_head()
            return syntax_setup.parser_after_token(token_parser)
    return default(token_parser)