# SPDX-License-Identifier: LGPL-2.1-only # Copyright 2022 Jookia <contact@jookia.org> import enum from src.syntax import Syntax, SyntaxType # Errors that can happen when parsing class ParseError(enum.Enum): NO_TOKEN = enum.auto() # pragma: no mutate NOT_TOKEN = enum.auto() # pragma: no mutate WRONG_TOKEN = enum.auto() # pragma: no mutate FOUND_STARTTEXT = enum.auto() # pragma: no mutate # Exception thrown when a parse error is encountered class ParseErrorException(BaseException): def __init__(self, error, syntax, expected): self.error = error self.syntax = syntax self.expected = expected def __str__(self): return ( "ParseErrorException(error %s, syntax %s, expected %s)" # pragma: no mutate % ( # pragma: no mutate self.error, self.syntax, self.expected, ) ) def __eq__(self, other): return ( self.error == other.error and self.syntax == other.syntax and self.expected == other.expected ) # Reads a token, possibly of a certain value def read_token(stream, value): s = stream.pop() if s is None: raise ParseErrorException(ParseError.NO_TOKEN, None, None) elif s.type != SyntaxType.TOKEN: raise ParseErrorException(ParseError.NOT_TOKEN, s, None) elif value is not None and s.value != value: raise ParseErrorException(ParseError.WRONG_TOKEN, s, value) return s # Parses a text syntax node def parse_text(stream): buffer = "" s = read_token(stream, "StartText") location = s.location # Parse following tokens while True: s = read_token(stream, None) # Don't allow StartText in text if s.value in ["StartText"]: raise ParseErrorException(ParseError.FOUND_STARTTEXT, s, None) # EndText found, end things elif s.value == "EndText": break else: buffer += s.value + " " type = SyntaxType.TEXT value = buffer[:-1] # Drop trailing space return Syntax(value, location, type) # Parses tokens def parse(tokens): return tokens