"""Fixer for generator.throw(E, V, T). g.throw(E) -> g.throw(E) g.throw(E, V) -> g.throw(E(V)) g.throw(E, V, T) -> g.throw(E(V).with_traceback(T)) g.throw("foo"[, V[, T]]) will warn about string exceptions.""" # Author: Collin Winter # Local imports from .. import pytree from ..pgen2 import token from .. import fixer_base from ..fixer_util import Name, Call, ArgList, Attr, is_tuple class FixThrow(fixer_base.BaseFix): BM_compatible = True PATTERN = """ power< any trailer< '.' 'throw' > trailer< '(' args=arglist< exc=any ',' val=any [',' tb=any] > ')' > > | power< any trailer< '.' 'throw' > trailer< '(' exc=any ')' > > """ def transform(self, node, results): syms = self.syms exc = results["exc"].clone() if exc.type is token.STRING: self.cannot_convert(node, "Python 3 does not support string exceptions") return # Leave "g.throw(E)" alone val = results.get("val") if val is None: return val = val.clone() if is_tuple(val): args = [c.clone() for c in val.children[1:-1]] else: val.prefix = "" args = [val] throw_args = results["args"] if "tb" in results: tb = results["tb"].clone() tb.prefix = "" e = Call(exc, args) with_tb = Attr(e, Name('with_traceback')) + [ArgList([tb])] throw_args.replace(pytree.Node(syms.power, with_tb)) else: throw_args.replace(Call(exc, args))