cpython/Lib/lib2to3/fixes/fix_except.py
Benjamin Peterson df6dc8f107 Merged revisions 64286 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r64286 | benjamin.peterson | 2008-06-14 21:31:05 -0500 (Sat, 14 Jun 2008) | 49 lines

  Merged revisions 63661,63666,63695,63711,63729,63769,63790,63880,63886 via svnmerge from
  svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3

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    r63661 | georg.brandl | 2008-05-26 05:26:20 -0500 (Mon, 26 May 2008) | 2 lines

    Add import fixes for dbm package.
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    r63666 | georg.brandl | 2008-05-26 05:49:09 -0500 (Mon, 26 May 2008) | 2 lines

    Add xmlrpc package fixes.
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    r63695 | georg.brandl | 2008-05-26 10:14:33 -0500 (Mon, 26 May 2008) | 2 lines

    Add fixer entries for http package.
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    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
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    r63729 | benjamin.peterson | 2008-05-26 16:31:03 -0500 (Mon, 26 May 2008) | 2 lines

    mapping for commands module -> subprocess
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    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.
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    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.
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    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.
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    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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2008-06-15 02:57:40 +00:00

92 lines
3.2 KiB
Python

"""Fixer for except statements with named exceptions.
The following cases will be converted:
- "except E, T:" where T is a name:
except E as T:
- "except E, T:" where T is not a name, tuple or list:
except E as t:
T = t
This is done because the target of an "except" clause must be a
name.
- "except E, T:" where T is a tuple or list literal:
except E as t:
T = t.args
"""
# Author: Collin Winter
# Local imports
from .. import pytree
from ..pgen2 import token
from .. import fixer_base
from ..fixer_util import Assign, Attr, Name, is_tuple, is_list, reversed
def find_excepts(nodes):
for i, n in enumerate(nodes):
if isinstance(n, pytree.Node):
if n.children[0].value == 'except':
yield (n, nodes[i+2])
class FixExcept(fixer_base.BaseFix):
PATTERN = """
try_stmt< 'try' ':' suite
cleanup=(except_clause ':' suite)+
tail=(['except' ':' suite]
['else' ':' suite]
['finally' ':' suite]) >
"""
def transform(self, node, results):
syms = self.syms
tail = [n.clone() for n in results["tail"]]
try_cleanup = [ch.clone() for ch in results["cleanup"]]
for except_clause, e_suite in find_excepts(try_cleanup):
if len(except_clause.children) == 4:
(E, comma, N) = except_clause.children[1:4]
comma.replace(Name("as", prefix=" "))
if N.type != token.NAME:
# Generate a new N for the except clause
new_N = Name(self.new_name(), prefix=" ")
target = N.clone()
target.set_prefix("")
N.replace(new_N)
new_N = new_N.clone()
# Insert "old_N = new_N" as the first statement in
# the except body. This loop skips leading whitespace
# and indents
#TODO(cwinter) suite-cleanup
suite_stmts = e_suite.children
for i, stmt in enumerate(suite_stmts):
if isinstance(stmt, pytree.Node):
break
# The assignment is different if old_N is a tuple or list
# In that case, the assignment is old_N = new_N.args
if is_tuple(N) or is_list(N):
assign = Assign(target, Attr(new_N, Name('args')))
else:
assign = Assign(target, new_N)
#TODO(cwinter) stopgap until children becomes a smart list
for child in reversed(suite_stmts[:i]):
e_suite.insert_child(0, child)
e_suite.insert_child(i, assign)
elif N.get_prefix() == "":
# No space after a comma is legal; no space after "as",
# not so much.
N.set_prefix(" ")
#TODO(cwinter) fix this when children becomes a smart list
children = [c.clone() for c in node.children[:3]] + try_cleanup + tail
return pytree.Node(node.type, children)