Handle Python 2 vs 3 raise syntax change

raise_stmt ::=  "raise" expression "," expression
becomes:
   raise_stmt ::=  "raise" expression from expression

raise expr, expr -> raise

NEWS

@@ -1,3 +1,10 @@
+uncompyle6 2.8.2 2016-08-29
+
+- Handle Python 3.6 format string conversions !r, !s, !a
+- Start to handle 3.1 bytecode
+- Fix some PyPy translation bugs
+- We now only handle 3.6.0a3+ since that is incompatible with 3.6 before that
+
 uncompyle6 2.8.1 2016-08-20
 
 - Add Python 2.2 decompilation

test/simple_source/bug26/03_raise_from.py

@@ -0,0 +1,9 @@
+# From 3.4 _pyio.py
+# Bug is change in syntax between Python 2 and 3:
+#    raise_stmt ::=  "raise" expression "," expression
+# becomes:
+#    raise_stmt ::=  "raise" expression from expression
+try:
+    x = 1
+except AttributeError as err:
+    raise TypeError("an integer is required"), err

test/simple_source/bug33/03_raise_from.py

@@ -0,0 +1,9 @@
+# From 3.4 _pyio.py
+# Bug is change in syntax between Python 2 and 3:
+#    raise_stmt ::=  "raise" expression "," expression
+# becomes:
+#    raise_stmt ::=  "raise" expression from expression
+try:
+    x = 1
+except AttributeError as err:
+    raise TypeError("an integer is required") from err

uncompyle6/semantics/pysource.py

@@ -278,7 +278,6 @@ TABLE_DIRECT = {
 
     'raise_stmt0':	( '%|raise\n', ),
     'raise_stmt1':	( '%|raise %c\n', 0),
-    'raise_stmt2':	( '%|raise %c, %c\n', 0, 1),
     'raise_stmt3':	( '%|raise %c, %c, %c\n', 0, 1, 2),
 #    'yield':	( 'yield %c', 0),
 #    'return_stmt':	( '%|return %c\n', 0),
@@ -547,7 +546,16 @@ class SourceWalker(GenericASTTraversal, object):
                 'DELETE_SLICE+1':	( '%|del %c[%c:]\n', 0, 1 ),
                 'DELETE_SLICE+2':	( '%|del %c[:%c]\n', 0, 1 ),
                 'DELETE_SLICE+3':	( '%|del %c[%c:%c]\n', 0, 1, 2 ),
-        })
+            })
+            TABLE_DIRECT.update({
+                'raise_stmt2':	( '%|raise %c, %c\n', 0, 1),
+            })
+        else:
+            # Gotta love Python for its futzing around with syntax like this
+            TABLE_DIRECT.update({
+                'raise_stmt2':	( '%|raise %c from %c\n', 0, 1),
+            })
+
 
         if 2.0 <= version <= 2.3:
             TABLE_DIRECT.update({