--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ply-3.8/test/yacc_error5.py	Wed Mar 23 02:40:16 2016 +0000
@@ -0,0 +1,94 @@
+# -----------------------------------------------------------------------------
+# yacc_error5.py
+#
+# Lineno and position tracking with error tokens
+# -----------------------------------------------------------------------------
+import sys
+
+if ".." not in sys.path: sys.path.insert(0,"..")
+import ply.yacc as yacc
+
+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_assign_error(t):
+    'statement : NAME EQUALS error'
+    line_start, line_end = t.linespan(3)
+    pos_start, pos_end = t.lexspan(3)
+    print("Assignment Error at %d:%d to %d:%d" % (line_start,pos_start,line_end,pos_end))
+
+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[2] == '/': 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'
+    line_start, line_end = t.linespan(2)
+    pos_start, pos_end = t.lexspan(2)
+    print("Group at %d:%d to %d:%d" % (line_start,pos_start, line_end, pos_end))
+    t[0] = t[2]
+
+def p_expression_group_error(t):
+    'expression : LPAREN error RPAREN'
+    line_start, line_end = t.linespan(2)
+    pos_start, pos_end = t.lexspan(2)
+    print("Syntax error at %d:%d to %d:%d" % (line_start,pos_start, line_end, pos_end))
+    t[0] = 0
+    
+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_error(t):
+    print("Syntax error at '%s'" % t.value)
+
+parser = yacc.yacc()
+import calclex
+calclex.lexer.lineno=1
+parser.parse("""
+a = 3 +
+(4*5) +
+(a b c) +
++ 6 + 7
+""", tracking=True)
+
+
+
+
+
+