Fixed a bug with negative stack indices

2 files changed, 42 insertions, 0 deletions

diff --git a/test/testyacc.py b/test/testyacc.py
index 4793986..08fb007 100644
--- a/test/testyacc.py
+++ b/test/testyacc.py
@@ -160,6 +160,15 @@ class YaccErrorWarningTests(unittest.TestCase):
                                     "yacc_missing1.py:24: Symbol 'location' used, but not defined as a token or a rule.\n"
                                     ))
 
+    def test_yacc_nested(self):
+        run_import("yacc_nested")
+        result = sys.stdout.getvalue()
+        self.assert_(check_expected(result,
+                                    "A\n"
+                                    "A\n"
+                                    "A\n",
+                                    ))
+
     def test_yacc_nodoc(self):
         run_import("yacc_nodoc")
         result = sys.stderr.getvalue()
diff --git a/test/yacc_nested.py b/test/yacc_nested.py
new file mode 100644
index 0000000..4c85013
--- /dev/null
+++ b/test/yacc_nested.py
@@ -0,0 +1,33 @@
+import sys
+
+if ".." not in sys.path: sys.path.insert(0,"..")
+
+from ply import lex, yacc
+
+t_A = 'A'
+t_B = 'B'
+t_C = 'C'
+
+tokens = ('A', 'B', 'C')
+
+the_lexer = lex.lex()
+
+def t_error(t):
+    pass
+
+def p_error(p):
+    pass
+
+def p_start(t):
+    '''start : A nest C'''
+    pass
+
+def p_nest(t):
+   '''nest : B'''
+   print t[-1]
+
+the_parser = yacc.yacc(debug = False, write_tables = False)
+
+the_parser.parse('ABC', the_lexer)
+the_parser.parse('ABC', the_lexer, tracking=True)
+the_parser.parse('ABC', the_lexer, tracking=True, debug=1)