rexdsl 0.0.3

custom regex dsl designed in rply for simplicity

• domain specific language designed for regex
• uses rply as engine

class Rex: def init(self, block: str): self._build_lexer() self._build_parser()

    tokens = self.lexer.lex(block)
    self.pattern = self.parser.parse(tokens)

def _build_lexer(self):
    rules = {
        "STRING":    r"'[^']*'",
        "NUMBER":    r"\d+",
        "OR":        r"(?i)or",
        "AND":       r"(?i)and",
        "SEMICOLON": r";",

        # constants
        "ALPHANUM":  r"_ALPHANUM",
    }

    lg = LexerGenerator()
    for name, pattern in rules.items():
        lg.add(name, pattern)

    lg.ignore(r"\s+")
    self.lexer = lg.build()

def _build_parser(self):
    pg = ParserGenerator(["STRING", "NUMBER", "ALPHANUM", "OR", "AND", "SEMICOLON"])

    # Start
    pg.production("start : sequences SEMICOLON")(lambda p: p[0])

    # OR sequences
    pg.production("sequences : sequence OR sequences")(lambda p: f"(?:{p[0]})|(?:{p[2]})")
    pg.production("sequences : sequence")(lambda p: p[0])

    # AND sequences
    pg.production("sequence : statement AND sequence")(lambda p: f"{p[0]}{p[2]}")
    pg.production("sequence : statement")(lambda p: p[0])

    # Unified statement handler
    def statement(p, x):
        tok_type = p[0].gettokentype()
        match tok_type:
            case "STRING":
                text = p[0].getstr()[1:-1]
            case "_ALPHANUM":
                text = r"[A-Za-z0-9]"
        count = int(p[1].getstr()) if x == 2 else 1
        return f"(?:{text}){{{count}}}"


    pg.production("statement : STRING NUMBER")(lambda p: statement(p, len(p)))
    pg.production("statement : STRING")(lambda p: statement(p, len(p)))
    pg.production("statement : ALPHANUM NUMBER")(lambda p: statement(p, len(p)))
    pg.production("statement : ALPHANUM")(lambda p: statement(p, len(p)))

    self.parser = pg.build()

def exists(self, block: str):
    return bool(regex.fullmatch(self.pattern, block))