Querying and tracing a DCG

You can download the DCG that we saw in the lecture here.

Load it and type listing. You will see that Prolog translated the user friendly --> notation to its internal DCG format.

To find out whether a list words L is a sentence, you have to ask the query s(L,[]). But you can also ask whether it is a noun phrase by asking np(L,[]), or whether it starts with a noun phrase by asking np(L,Rest).