93 lines
3.2 KiB
Python
93 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, syms
|
|
|
|
def find_excepts(nodes):
|
|
for i, n in enumerate(nodes):
|
|
if n.type == syms.except_clause:
|
|
if n.children[0].value == u'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(u"as", prefix=u" "))
|
|
|
|
if N.type != token.NAME:
|
|
# Generate a new N for the except clause
|
|
new_N = Name(self.new_name(), prefix=u" ")
|
|
target = N.clone()
|
|
target.set_prefix(u"")
|
|
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(u'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() == u"":
|
|
# No space after a comma is legal; no space after "as",
|
|
# not so much.
|
|
N.set_prefix(u" ")
|
|
|
|
#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)
|