1 files changed, 76 insertions, 0 deletions
diff --git a/ext/ply/test/yacc_unused.py b/ext/ply/test/yacc_unused.py
new file mode 100644
index 000000000..4cbd63327
--- /dev/null
+++ b/ext/ply/test/yacc_unused.py
@@ -0,0 +1,76 @@
+# -----------------------------------------------------------------------------
+# yacc_unused.py
+#
+# A grammar with an unused rule
+# -----------------------------------------------------------------------------
+import sys
+sys.tracebacklimit = 0
+
+from calclex import tokens
+
+# Parsing rules
+precedence = (
+    ('left','PLUS','MINUS'),
+    ('left','TIMES','DIVIDE'),
+    ('right','UMINUS'),
+    )
+
+# dictionary of names
+names = { }
+
+def p_statement_assign(t):
+    'statement : NAME EQUALS expression'
+    names[t[1]] = t[3]
+
+def p_statement_expr(t):
+    'statement : expression'
+    print t[1]
+
+def p_expression_binop(t):
+    '''expression : expression PLUS expression
+                  | expression MINUS expression
+                  | expression TIMES expression
+                  | expression DIVIDE expression'''
+    if t[2] == '+'  : t[0] = t[1] + t[3]
+    elif t[2] == '-': t[0] = t[1] - t[3]
+    elif t[2] == '*': t[0] = t[1] * t[3]
+    elif t[3] == '/': t[0] = t[1] / t[3]
+
+def p_expression_uminus(t):
+    'expression : MINUS expression %prec UMINUS'
+    t[0] = -t[2]
+
+def p_expression_group(t):
+    'expression : LPAREN expression RPAREN'
+    t[0] = t[2]
+
+def p_expression_number(t):
+    'expression : NUMBER'
+    t[0] = t[1]
+
+def p_expression_name(t):
+    'expression : NAME'
+    try:
+        t[0] = names[t[1]]
+    except LookupError:
+        print "Undefined name '%s'" % t[1]
+        t[0] = 0
+
+def p_expr_list(t):
+    'exprlist : exprlist COMMA expression'
+    pass
+
+def p_expr_list_2(t):
+    'exprlist : expression'
+    pass
+
+
+def p_error(t):
+    print "Syntax error at '%s'" % t.value
+
+import yacc
+yacc.yacc()
+
+
+
+