def _read_regex(ctx: ReaderContext) -> Pattern:
s = _read_str(ctx, allow_arbitrary_escapes=True)<EOL>try:<EOL><INDENT>return langutil.regex_from_str(s)<EOL><DEDENT>except re.error:<EOL><INDENT>raise SyntaxError(f"<STR_LIT>")<EOL><DEDENT>
Read a regex reader macro from the input stream.