cpython/Lib/lib2to3/fixes/fix_raise.py

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"""Fixer for 'raise E, V, T'
raise -> raise
raise E -> raise E
raise E, V -> raise E(V)
raise E, V, T -> raise E(V).with_traceback(T)
raise (((E, E'), E''), E'''), V -> raise E(V)
raise "foo", V, T -> warns about string exceptions
CAVEATS:
1) "raise E, V" will be incorrectly translated if V is an exception
instance. The correct Python 3 idiom is
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raise E from V
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but since we can't detect instance-hood by syntax alone and since
any client code would have to be changed as well, we don't automate
this.
"""
# Author: Collin Winter
# Local imports
from .. import pytree
from ..pgen2 import token
Merged revisions 63661,63666,63695,63711,63729,63769,63790,63880,63886 via svnmerge from svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3 ........ r63661 | georg.brandl | 2008-05-26 05:26:20 -0500 (Mon, 26 May 2008) | 2 lines Add import fixes for dbm package. ........ r63666 | georg.brandl | 2008-05-26 05:49:09 -0500 (Mon, 26 May 2008) | 2 lines Add xmlrpc package fixes. ........ r63695 | georg.brandl | 2008-05-26 10:14:33 -0500 (Mon, 26 May 2008) | 2 lines Add fixer entries for http package. ........ r63711 | benjamin.peterson | 2008-05-26 13:43:51 -0500 (Mon, 26 May 2008) | 2 lines add import mapping for test.test_support -> test.support ........ r63729 | benjamin.peterson | 2008-05-26 16:31:03 -0500 (Mon, 26 May 2008) | 2 lines mapping for commands module -> subprocess ........ r63769 | brett.cannon | 2008-05-29 00:13:13 -0500 (Thu, 29 May 2008) | 1 line Fixer for UserString.UserString over to the collections module. ........ r63790 | brett.cannon | 2008-05-29 14:13:51 -0500 (Thu, 29 May 2008) | 4 lines Add a fixer for UserList. Closes issue #2878. Thanks to Quentin Gallet-Gilles for the patch. ........ r63880 | collin.winter | 2008-06-01 18:09:38 -0500 (Sun, 01 Jun 2008) | 6 lines Move lib2to3/fixes/{basefix,util}.py down to lib2to3/. This is step 1 of turning lib2to3/ into a general-purpose refactoring library, reusable by other projects. ........ r63886 | collin.winter | 2008-06-01 22:15:01 -0500 (Sun, 01 Jun 2008) | 5 lines Allow refactoring tools to specify a directory for fixer modules. This is step 2 of turning lib2to3/ into a general-purpose refactoring library, reusable by other projects. Step 1: r63880. ........
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from .. import fixer_base
from ..fixer_util import Name, Call, Attr, ArgList, is_tuple
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Merged revisions 63661,63666,63695,63711,63729,63769,63790,63880,63886 via svnmerge from svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3 ........ r63661 | georg.brandl | 2008-05-26 05:26:20 -0500 (Mon, 26 May 2008) | 2 lines Add import fixes for dbm package. ........ r63666 | georg.brandl | 2008-05-26 05:49:09 -0500 (Mon, 26 May 2008) | 2 lines Add xmlrpc package fixes. ........ r63695 | georg.brandl | 2008-05-26 10:14:33 -0500 (Mon, 26 May 2008) | 2 lines Add fixer entries for http package. ........ r63711 | benjamin.peterson | 2008-05-26 13:43:51 -0500 (Mon, 26 May 2008) | 2 lines add import mapping for test.test_support -> test.support ........ r63729 | benjamin.peterson | 2008-05-26 16:31:03 -0500 (Mon, 26 May 2008) | 2 lines mapping for commands module -> subprocess ........ r63769 | brett.cannon | 2008-05-29 00:13:13 -0500 (Thu, 29 May 2008) | 1 line Fixer for UserString.UserString over to the collections module. ........ r63790 | brett.cannon | 2008-05-29 14:13:51 -0500 (Thu, 29 May 2008) | 4 lines Add a fixer for UserList. Closes issue #2878. Thanks to Quentin Gallet-Gilles for the patch. ........ r63880 | collin.winter | 2008-06-01 18:09:38 -0500 (Sun, 01 Jun 2008) | 6 lines Move lib2to3/fixes/{basefix,util}.py down to lib2to3/. This is step 1 of turning lib2to3/ into a general-purpose refactoring library, reusable by other projects. ........ r63886 | collin.winter | 2008-06-01 22:15:01 -0500 (Sun, 01 Jun 2008) | 5 lines Allow refactoring tools to specify a directory for fixer modules. This is step 2 of turning lib2to3/ into a general-purpose refactoring library, reusable by other projects. Step 1: r63880. ........
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class FixRaise(fixer_base.BaseFix):
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PATTERN = """
raise_stmt< 'raise' exc=any [',' val=any [',' tb=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
# Python 2 supports
# raise ((((E1, E2), E3), E4), E5), V
# as a synonym for
# raise E1, V
# Since Python 3 will not support this, we recurse down any tuple
# literals, always taking the first element.
if is_tuple(exc):
while is_tuple(exc):
# exc.children[1:-1] is the unparenthesized tuple
# exc.children[1].children[0] is the first element of the tuple
exc = exc.children[1].children[0].clone()
exc.set_prefix(" ")
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if "val" not in results:
# One-argument raise
new = pytree.Node(syms.raise_stmt, [Name("raise"), exc])
new.set_prefix(node.get_prefix())
return new
val = results["val"].clone()
if is_tuple(val):
args = [c.clone() for c in val.children[1:-1]]
else:
val.set_prefix("")
args = [val]
if "tb" in results:
tb = results["tb"].clone()
tb.set_prefix("")
e = Call(exc, args)
with_tb = Attr(e, Name('with_traceback')) + [ArgList([tb])]
new = pytree.Node(syms.simple_stmt, [Name("raise")] + with_tb)
new.set_prefix(node.get_prefix())
return new
else:
return pytree.Node(syms.raise_stmt,
[Name("raise"), Call(exc, args)],
prefix=node.get_prefix())