def __from_string_inner(cls, sexp):
if not isinstance(sexp, tuple):
return sexp
if sexp[0] == cls.LAMBDA:
return (sexp[0], sexp[1], parse_bracketed('<', '>', sexp[2], ','),
cls.__from_string_inner(sexp[3]))
return tuple(cls.__from_string_inner(child) for child in sexp)
def from_string(cls, string):
sexp = parse_bracketed('(', ')', string)
sexp = cls.__from_string_inner(sexp)
return LambdaExpr(sexp)