Folks this is a parser for Context Free Grammars, for some reason when
I go simplify the grammar trying to remove productions that substitute
variables like in the case:

S -> A, A -> B, B -> a, it works perfectly and returns S ->
a, the problem is when the root symbol is on the listthat must be
replaced as in:

S -> aXa | bXb , X -> a | b | S | £(empty)

instead of returning

S -> aXa | bXb, X -> a | b | £ | aXa | bXb

it ruturns X as

X -> a | b | £ | S <- this S is wrong! it should return X -> a
| b | £ | aXa | bXb! Im not sure about where is the mistake. If you can
give me hints it would be grat. I will be checking the mail and also
hanging over #haskell at freenode ifyou want to contact me directly.
Thanks in advance for the help!

Victor

_______________________________________________

Haskell-Cafe mailing list

[hidden email]
http://www.haskell.org/mailman/listinfo/haskell-cafe