Parsing numbers with multiple digits in Prolog

Question

I have the following simple expression parser:

expr(+(T,E))-->term(T),\"+\",expr(E).
expr(T)-->term(T).

term(*(F,T))-->factor(F),\"*\",term(T).
ter         


        

Answer 1

Can you provide a sample input?

I think this might work:

nat(N)-->number(N).

If that fails try:

nat(N)-->number(N),!.

The ! is a cut it stops the unification. You can read about it in books/tutorials.