Add future 0.18.2

lib/libfuturize/fixes/fix_division_safe.py

@@ -0,0 +1,104 @@
+"""
+For the ``future`` package.
+
+Adds this import line:
+
+    from __future__ import division
+
+at the top and changes any old-style divisions to be calls to
+past.utils.old_div so the code runs as before on Py2.6/2.7 and has the same
+behaviour on Py3.
+
+If "from __future__ import division" is already in effect, this fixer does
+nothing.
+"""
+
+import re
+from lib2to3.fixer_util import Leaf, Node, Comma
+from lib2to3 import fixer_base
+from libfuturize.fixer_util import (token, future_import, touch_import_top,
+                                    wrap_in_fn_call)
+
+
+def match_division(node):
+    u"""
+    __future__.division redefines the meaning of a single slash for division,
+    so we match that and only that.
+    """
+    slash = token.SLASH
+    return node.type == slash and not node.next_sibling.type == slash and \
+                                  not node.prev_sibling.type == slash
+
+const_re = re.compile('^[0-9]*[.][0-9]*$')
+
+def is_floaty(node):
+    return _is_floaty(node.prev_sibling) or _is_floaty(node.next_sibling)
+
+
+def _is_floaty(expr):
+    if isinstance(expr, list):
+        expr = expr[0]
+
+    if isinstance(expr, Leaf):
+        # If it's a leaf, let's see if it's a numeric constant containing a '.'
+        return const_re.match(expr.value)
+    elif isinstance(expr, Node):
+        # If the expression is a node, let's see if it's a direct cast to float
+        if isinstance(expr.children[0], Leaf):
+            return expr.children[0].value == u'float'
+    return False
+
+
+class FixDivisionSafe(fixer_base.BaseFix):
+    # BM_compatible = True
+    run_order = 4    # this seems to be ignored?
+
+    _accept_type = token.SLASH
+
+    PATTERN = """
+    term<(not('/') any)+ '/' ((not('/') any))>
+    """
+
+    def start_tree(self, tree, name):
+        """
+        Skip this fixer if "__future__.division" is already imported.
+        """
+        super(FixDivisionSafe, self).start_tree(tree, name)
+        self.skip = "division" in tree.future_features
+
+    def match(self, node):
+        u"""
+        Since the tree needs to be fixed once and only once if and only if it
+        matches, we can start discarding matches after the first.
+        """
+        if node.type == self.syms.term:
+            matched = False
+            skip = False
+            children = []
+            for child in node.children:
+                if skip:
+                    skip = False
+                    continue
+                if match_division(child) and not is_floaty(child):
+                    matched = True
+
+                    # Strip any leading space for the first number:
+                    children[0].prefix = u''
+
+                    children = [wrap_in_fn_call("old_div",
+                                                children + [Comma(), child.next_sibling.clone()],
+                                                prefix=node.prefix)]
+                    skip = True
+                else:
+                    children.append(child.clone())
+            if matched:
+                return Node(node.type, children, fixers_applied=node.fixers_applied)
+
+        return False
+
+    def transform(self, node, results):
+        if self.skip:
+            return
+        future_import(u"division", node)
+        touch_import_top(u'past.utils', u'old_div', node)
+        return results