105 lines
3.2 KiB
Python
105 lines
3.2 KiB
Python
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"""
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For the ``future`` package.
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Adds this import line:
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from __future__ import division
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at the top and changes any old-style divisions to be calls to
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past.utils.old_div so the code runs as before on Py2.6/2.7 and has the same
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behaviour on Py3.
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If "from __future__ import division" is already in effect, this fixer does
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nothing.
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"""
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import re
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from lib2to3.fixer_util import Leaf, Node, Comma
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from lib2to3 import fixer_base
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from libfuturize.fixer_util import (token, future_import, touch_import_top,
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wrap_in_fn_call)
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def match_division(node):
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u"""
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__future__.division redefines the meaning of a single slash for division,
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so we match that and only that.
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"""
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slash = token.SLASH
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return node.type == slash and not node.next_sibling.type == slash and \
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not node.prev_sibling.type == slash
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const_re = re.compile('^[0-9]*[.][0-9]*$')
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def is_floaty(node):
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return _is_floaty(node.prev_sibling) or _is_floaty(node.next_sibling)
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def _is_floaty(expr):
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if isinstance(expr, list):
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expr = expr[0]
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if isinstance(expr, Leaf):
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# If it's a leaf, let's see if it's a numeric constant containing a '.'
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return const_re.match(expr.value)
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elif isinstance(expr, Node):
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# If the expression is a node, let's see if it's a direct cast to float
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if isinstance(expr.children[0], Leaf):
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return expr.children[0].value == u'float'
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return False
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class FixDivisionSafe(fixer_base.BaseFix):
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# BM_compatible = True
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run_order = 4 # this seems to be ignored?
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_accept_type = token.SLASH
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PATTERN = """
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term<(not('/') any)+ '/' ((not('/') any))>
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"""
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def start_tree(self, tree, name):
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"""
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Skip this fixer if "__future__.division" is already imported.
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"""
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super(FixDivisionSafe, self).start_tree(tree, name)
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self.skip = "division" in tree.future_features
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def match(self, node):
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u"""
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Since the tree needs to be fixed once and only once if and only if it
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matches, we can start discarding matches after the first.
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"""
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if node.type == self.syms.term:
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matched = False
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skip = False
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children = []
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for child in node.children:
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if skip:
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skip = False
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continue
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if match_division(child) and not is_floaty(child):
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matched = True
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# Strip any leading space for the first number:
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children[0].prefix = u''
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children = [wrap_in_fn_call("old_div",
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children + [Comma(), child.next_sibling.clone()],
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prefix=node.prefix)]
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skip = True
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else:
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children.append(child.clone())
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if matched:
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return Node(node.type, children, fixers_applied=node.fixers_applied)
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return False
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def transform(self, node, results):
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if self.skip:
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return
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future_import(u"division", node)
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touch_import_top(u'past.utils', u'old_div', node)
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return results
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