Merge pull request #269 from rocky/if-elif-else-more

If elif else more

test/simple_source/bug34/08_while_if.py

@@ -0,0 +1,34 @@
+# Testing "while 1" versus "while" handling with if/elif/else's
+
+def while_test(a, b, c):
+    while a != 2:
+        if b:
+            a += 1
+        elif c:
+            c = 0
+        else:
+            break
+    return a, b, c
+
+
+def while1_test(a, b, c):
+    while 1:
+        if a != 2:
+            if b:
+                a = 3
+                b = 0
+            elif c:
+                c = 0
+            else:
+                a += b + c
+                break
+    return a, b, c
+
+
+assert while_test(2, 0, 0) == (2, 0, 0), "no while loops"
+assert while_test(0, 1, 0) == (2, 1, 0), "two while loops of b branch"
+assert while_test(0, 0, 0) == (0, 0, 0), "0 while loops, else branch"
+
+# FIXME: put this in a timer, and try with a=2
+assert while1_test(4, 1, 1) == (3, 0, 0), "three while1 loops"
+assert while1_test(4, 0, 0) == (4, 0, 0), " one while1 loop"

uncompyle6/parsers/parse3.py

@@ -152,11 +152,8 @@ class Python3Parser(PythonParser):
         _ifstmts_jump ::= return_if_stmts
         _ifstmts_jump ::= c_stmts_opt COME_FROM
 
-        iflaststmt ::= testexpr c_stmts_opt JUMP_ABSOLUTE
-
+        iflaststmt  ::= testexpr c_stmts_opt JUMP_ABSOLUTE
         iflaststmtl ::= testexpr c_stmts_opt JUMP_BACK
-        iflaststmtl ::= testexpr c_stmts_opt JUMP_BACK COME_FROM_LOOP
-        iflaststmtl ::= testexpr c_stmts_opt JUMP_BACK POP_BLOCK
 
         # These are used to keep parse tree indices the same
         jump_forward_else  ::= JUMP_FORWARD ELSE
@@ -182,6 +179,8 @@ class Python3Parser(PythonParser):
 
         ifelsestmtl ::= testexpr c_stmts_opt JUMP_BACK else_suitel
         ifelsestmtl ::= testexpr c_stmts_opt cf_jump_back else_suitel
+        ifelsestmtl ::= testexpr c_stmts_opt continue else_suitel
+
 
         cf_jump_back ::= COME_FROM JUMP_BACK
 
@@ -348,6 +347,8 @@ class Python3Parser(PythonParser):
 
     def p_loop_stmt3(self, args):
         """
+        stmt ::= whileelsestmt2
+
         for               ::= SETUP_LOOP expr for_iter store for_block POP_BLOCK
                               COME_FROM_LOOP
 
@@ -363,6 +364,8 @@ class Python3Parser(PythonParser):
         whilestmt         ::= SETUP_LOOP testexpr l_stmts_opt COME_FROM JUMP_BACK POP_BLOCK
                               COME_FROM_LOOP
 
+        whilestmt         ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK POP_BLOCK JUMP_BACK
+                              COME_FROM_LOOP
         whilestmt         ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK POP_BLOCK
                               COME_FROM_LOOP
 
@@ -375,6 +378,9 @@ class Python3Parser(PythonParser):
         whileelsestmt     ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK POP_BLOCK
                               else_suitel COME_FROM_LOOP
 
+        whileelsestmt2     ::= SETUP_LOOP testexpr l_stmts_opt  JUMP_BACK POP_BLOCK
+                              else_suitel JUMP_BACK COME_FROM_LOOP
+
         whileTruestmt     ::= SETUP_LOOP l_stmts_opt          JUMP_BACK POP_BLOCK
                               COME_FROM_LOOP
 

uncompyle6/semantics/consts.py

@@ -377,6 +377,7 @@ TABLE_DIRECT = {
     'while1stmt':	    ( '%|while 1:\n%+%c%-\n\n', 1 ),
     'while1elsestmt':   ( '%|while 1:\n%+%c%-%|else:\n%+%c%-\n\n', 1, -2 ),
     'whileelsestmt':	( '%|while %c:\n%+%c%-%|else:\n%+%c%-\n\n', 1, 2, -2 ),
+    'whileelsestmt2':	( '%|while %c:\n%+%c%-%|else:\n%+%c%-\n\n', 1, 2, -3 ),
     'whileelselaststmt':	( '%|while %c:\n%+%c%-%|else:\n%+%c%-', 1, 2, -2 ),
 
     # Note: Python 3.8+ changes this

uncompyle6/semantics/pysource.py

@@ -661,21 +661,33 @@ class SourceWalker(GenericASTTraversal, object):
           if ..
           elif ...
 
+          [else ...]
+
         where appropriate
         """
         else_suite = node[3]
 
         n = else_suite[0]
+        old_stmts = None
 
         if len(n) == 1 == len(n[0]) and n[0] == 'stmt':
             n = n[0][0]
         elif n[0].kind in ('lastc_stmt', 'lastl_stmt'):
             n = n[0]
-            if n[0].kind in ('ifstmt', 'iflaststmt', 'ifelsestmtl'):
+            if n[0].kind in ('ifstmt', 'iflaststmt', 'iflaststmtl', 'ifelsestmtl', 'ifelsestmtc'):
                 # This seems needed for Python 2.5-2.7
                 n = n[0]
                 pass
             pass
+        elif ( len(n) > 1 and 1 == len(n[0]) and n[0] == 'stmt'
+               and n[1].kind == "stmt" ):
+            else_suite_stmts = n[0]
+            if else_suite_stmts[0].kind not in ('ifstmt', 'iflaststmt', 'ifelsestmtl'):
+                if not preprocess:
+                    self.default(node)
+                return
+            old_stmts = n
+            n = else_suite_stmts[0]
         else:
             if not preprocess:
                 self.default(node)
@@ -695,6 +707,18 @@ class SourceWalker(GenericASTTraversal, object):
             elif n.kind in ('ifelsestmt', 'ifelsestmtc', 'ifelsestmtl'):
                 n.kind = 'elifelsestmt'
         if not preprocess:
+            if old_stmts:
+                if n.kind == "elifstmt":
+                    trailing_else = SyntaxTree("stmts", old_stmts[1:])
+                    # We use elifelsestmtr because it has 3 nodes
+                    elifelse_stmt = SyntaxTree(
+                        'elifelsestmtr', [n[0], n[1], trailing_else])
+                    node[3] = elifelse_stmt
+                    pass
+                else:
+                    # Other cases for n.kind may happen here
+                    return
+                pass
             self.default(node)
 
     n_ifelsestmtc = n_ifelsestmtl = n_ifelsestmt