Towards Python3 getting try/except working more often.

test/simple_source/exception/25_try_except.py

@@ -19,3 +19,23 @@ except ImportError:
     x = 3
 finally:
     x = 4
+
+# Tests Python3:
+#   trystmt ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK try_middle come_froms
+#   come_froms ::= COME_FROM COME_FROM
+#   START ::= |- stmts
+#   stmts ::= sstmt
+#   sstmt ::= stmt
+#   stmt ::= trystmt
+#   trystmt ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK try_middle come_froms
+#   come_froms ::= COME_FROM
+#   try_middle ::= JUMP_FORWARD COME_FROM except_stmts END_FINALLY COME_FROM
+# Python2 doesn't have the come_froms (which allows for 3 successive COME_FROMs)
+# it does place 2 COME_FROMs at the end of this code.
+
+try:
+    x = 1
+except SystemExit:
+    x = 2
+except:
+    x = 3

test/test_pythonlib.py

@@ -76,6 +76,8 @@ for  vers in (2.5, 2.6, 2.7, 3.2, 3.3, 3.4):
     test_options[key] =  (bytecode, PYC, bytecode, vers)
     key = "%s" % vers
     pythonlib = "python%s" % vers
+    if vers >= 3.0:
+        pythonlib = os.path.join(pythonlib, '__pycache__')
     test_options[key] =  (os.path.join(lib_prefix, pythonlib), PYC, pythonlib, vers)
 
 #-----

uncompyle6/parsers/parse3.py

@@ -228,8 +228,7 @@ class Python3Parser(PythonParser):
         '''
 
     def p_grammar(self, args):
-        '''
+        '''stmts ::= stmts sstmt
-        stmts ::= stmts sstmt
         stmts ::= sstmt
         sstmt ::= stmt
         sstmt ::= ifelsestmtr
@@ -405,6 +404,10 @@ class Python3Parser(PythonParser):
         testfalse ::= expr jmp_false
         testtrue ::= expr jmp_true
 
+        come_froms :: = COME_FROM COME_FROM
+        come_froms :: = COME_FROM
+
+
         _ifstmts_jump ::= return_if_stmts
         _ifstmts_jump ::= c_stmts_opt JUMP_FORWARD COME_FROM _come_from
 
@@ -421,8 +424,16 @@ class Python3Parser(PythonParser):
         ifelsestmtl ::= testexpr c_stmts_opt JUMP_BACK else_suitel
 
 
+        # FIXME: this feels like a hack. Is it just 1 or two
+        # COME_FROMs?  the parsed tree for this and even with just the
+        # one COME_FROM for Python 2.7 seems to associate the
+        # COME_FROM targets from the wrong places
+
+        come_froms ::= COME_FROM COME_FROM
+        come_froms ::= COME_FROM
+
         trystmt        ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
-                           try_middle COME_FROM
+                           try_middle come_froms
 
         # this is nested inside a trystmt
         tryfinallystmt ::= SETUP_FINALLY suite_stmts
@@ -450,6 +461,7 @@ class Python3Parser(PythonParser):
         except_stmt ::= except_cond2 except_suite
         except_stmt ::= except_cond2 except_suite_finalize
         except_stmt ::= except
+        except_stmt ::= except_pop_except
 
         # Python3 introduced POP_EXCEPT
         except_suite ::= c_stmts_opt POP_EXCEPT JUMP_FORWARD
@@ -471,11 +483,12 @@ class Python3Parser(PythonParser):
         except_cond2 ::= DUP_TOP expr COMPARE_OP
                 jmp_false POP_TOP designator POP_TOP
 
-        except  ::=  POP_TOP POP_TOP POP_TOP POP_EXCEPT c_stmts_opt JUMP_FORWARD
+        except  ::=  POP_TOP POP_TOP POP_TOP c_stmts_opt POP_EXCEPT JUMP_FORWARD
-        except  ::=  POP_TOP POP_TOP POP_TOP c_stmts_opt JUMP_FORWARD
-        except  ::=  POP_TOP POP_TOP POP_TOP POP_EXCEPT c_stmts_opt jmp_abs
         except  ::=  POP_TOP POP_TOP POP_TOP return_stmts
 
+        except_pop_except  ::=  POP_TOP POP_TOP POP_TOP POP_EXCEPT c_stmts_opt JUMP_FORWARD
+        except_pop_except  ::=  POP_TOP POP_TOP POP_TOP POP_EXCEPT c_stmts_opt jmp_abs
+
         jmp_abs ::= JUMP_ABSOLUTE
         jmp_abs ::= JUMP_BACK
 

uncompyle6/scanners/scanner27.py

@@ -618,7 +618,8 @@ class Scanner27(scan.Scanner):
         for i in self.op_range(0, n):
             op = code[i]
 
-            # Determine structures and fix jumps for 2.3+
+            # Determine structures and fix jumps in Python versions
+            # since 2.3
             self.detect_structure(i, op)
 
             if op >= HAVE_ARGUMENT:

uncompyle6/scanners/scanner3.py

@@ -313,7 +313,8 @@ class Scanner3(scan.Scanner):
         for offset in self.op_range(0, codelen):
             op = code[offset]
 
-            # Determine structures and fix jumps for 2.3+
+            # Determine structures and fix jumps in Python versions
+            # since 2.3
             self.detect_structure(offset)
 
             if op >= op3.HAVE_ARGUMENT:
@@ -322,7 +323,7 @@ class Scanner3(scan.Scanner):
 
                 if label is None:
                     if op in op3.hasjrel and op != FOR_ITER:
-                        label = offset + 3 + oparg
+                        label = offset + self.op_size(op) + oparg
                     elif op in op3.hasjabs:
                         if op in (JUMP_IF_FALSE_OR_POP, JUMP_IF_TRUE_OR_POP):
                             if oparg > offset:

uncompyle6/scanners/scanner34.py

@@ -183,49 +183,7 @@ class Scanner34(scan3.Scanner3):
                 parent = struct
                 pass
 
-        if op == SETUP_EXCEPT:
+        if op in (POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE):
-            start  = offset + 3
-            target = self.get_target(offset)
-            end    = self.restrict_to_parent(target, parent)
-            if target != end:
-                self.fixed_jumps[pos] = end
-                # print target, end, parent
-            # Add the try block
-            self.structs.append({'type':  'try',
-                                   'start': start,
-                                   'end':   end-4})
-            # Now isolate the except and else blocks
-            end_else = start_else = self.get_target(self.prev_op[end])
-
-            # Add the except blocks
-            i = end
-            while self.code[i] != END_FINALLY:
-                jmp = self.next_except_jump(i)
-                if self.code[jmp] == RETURN_VALUE:
-                    self.structs.append({'type':  'except',
-                                           'start': i,
-                                           'end':   jmp+1})
-                    i = jmp + 1
-                else:
-                    if self.get_target(jmp) != start_else:
-                        end_else = self.get_target(jmp)
-                    if self.code[jmp] == JUMP_FORWARD:
-                        self.fixed_jumps[jmp] = -1
-                    self.structs.append({'type':  'except',
-                                         'start': i,
-                                         'end':   jmp})
-                    i = jmp + 3
-
-            # Add the try-else block
-            if end_else != start_else:
-                r_end_else = self.restrict_to_parent(end_else, parent)
-                self.structs.append({'type':  'try-else',
-                                       'start': i+1,
-                                       'end':   r_end_else})
-                self.fixed_jumps[i] = r_end_else
-            else:
-                self.fixed_jumps[i] = i+1
-        elif op in (POP_JUMP_IF_FALSE, POP_JUMP_IF_TRUE):
             start = offset + self.op_size(op)
             target = self.get_target(offset)
             rtarget = self.restrict_to_parent(target, parent)

uncompyle6/semantics/pysource.py

@@ -317,6 +317,8 @@ TABLE_DIRECT = {
     'tryelsestmtl':		( '%|try:\n%+%c%-%c%|else:\n%+%c%-', 1, 3, 4 ),
     'tf_trystmt':		( '%c%-%c%+', 1, 3 ),
     'tf_tryelsestmt':		( '%c%-%c%|else:\n%+%c', 1, 3, 4 ),
+    'except':                   ('%|except:\n%+%c%-', 3 ),
+    'except_pop_except':        ('%|except:\n%+%c%-', 4 ),
     'except_cond1':	( '%|except %c:\n', 1 ),
     'except_cond2':	( '%|except %c as %c:\n', 1, 5 ),
     'except_suite':     ( '%+%c%-%C', 0, (1, maxint, '') ),
@@ -503,12 +505,6 @@ class Walker(GenericASTTraversal, object):
         self.pending_newlines = 0
         self.hide_internal = True
 
-        if version >= 3.0:
-            # Python 3 adds a POP_EXCEPT instruction
-            TABLE_DIRECT['except'] =  ('%|except:\n%+%c%-', 4 )
-        else:
-            TABLE_DIRECT['except'] =  ('%|except:\n%+%c%-', 3 )
-            pass
         return
 
     f = property(lambda s: s.params['f'],
@@ -1251,7 +1247,6 @@ class Walker(GenericASTTraversal, object):
         # self.print_("-----")
         # self.print(startnode)
 
-
         fmt = entry[0]
         arg = 1
         i = 0