[Python-checkins] r57420 - in sandbox/trunk/2to3: README fixes/fix_type_equality.py tests/test_fixers.py

[collin.winter]

Author: collin.winter
Date: Sat Aug 25 00:01:39 2007
New Revision: 57420

Added:
   sandbox/trunk/2to3/fixes/fix_type_equality.py
Modified:
   sandbox/trunk/2to3/   (props changed)
   sandbox/trunk/2to3/README
   sandbox/trunk/2to3/tests/test_fixers.py
Log:
Add an initial draft of fix_type_equality by Jacques Frechet.


Modified: sandbox/trunk/2to3/README
==============================================================================
--- sandbox/trunk/2to3/README	(original)
+++ sandbox/trunk/2to3/README	Sat Aug 25 00:01:39 2007
@@ -83,6 +83,8 @@
 
 * **fix_tuple_params** - remove tuple parameters from function, method and
   lambda declarations (PEP 3113).
+
+* **fix_type_equality** - convert type(x) == T to isinstance(x, T).
   
 * **fix_unicode** - convert, e.g., u"..." to "...", unicode(x) to str(x), etc.
   

Added: sandbox/trunk/2to3/fixes/fix_type_equality.py
==============================================================================
--- (empty file)
+++ sandbox/trunk/2to3/fixes/fix_type_equality.py	Sat Aug 25 00:01:39 2007
@@ -0,0 +1,21 @@
+"""Fix type(x) == T -> isinstance(x, T)."""
+# Author: Jacques Frechet
+
+# Local imports
+from fixes import basefix
+from fixes.util import Call, Comma, Name
+
+
+class FixTypeEquality(basefix.BaseFix):
+
+    PATTERN = """
+        comparison< power< 'type' trailer< '(' x=any ')' > > '==' T=any > |
+        comparison< T=any '==' power< 'type' trailer< '(' x=any ')' > > >
+    """
+
+    def transform(self, node, results):
+        x = results['x'].clone() # The thing inside of type()
+        T = results['T'].clone() # The type being compared against
+        x.set_prefix('')
+        T.set_prefix(' ')
+        return Call(Name('isinstance'), [x, Comma(), T])

Modified: sandbox/trunk/2to3/tests/test_fixers.py
==============================================================================
--- sandbox/trunk/2to3/tests/test_fixers.py	(original)
+++ sandbox/trunk/2to3/tests/test_fixers.py	Sat Aug 25 00:01:39 2007
@@ -2348,6 +2348,32 @@
         a = """int"""
         self.check(b, a)
 
+class Test_type_equality(FixerTestCase):
+    fixer = "type_equality"
+
+    def test_simple(self):
+        b = """type(x) == T"""
+        a = """isinstance(x, T)"""
+        self.check(b, a)
+
+    def test_reverse(self):
+        b = """T == type(x)"""
+        a = """isinstance(x, T)"""
+        self.check(b, a)
+
+    def test_expression(self):
+        b = """type(x+y) == d.get('T')"""
+        a = """isinstance(x+y, d.get('T'))"""
+        self.check(b, a)
+
+        b = """type(   x  +  y) == d.get('T')"""
+        a = """isinstance(x  +  y, d.get('T'))"""
+        self.check(b, a)
+
+    def test_unchanged(self):
+        a = """type(x).__name__"""
+        self.unchanged(a)
+
 
 if __name__ == "__main__":
     import __main__