Want to get minimal term_expansion example working

[kuniaki.mukai]

@robert314

I want to: write a prolog file that when consulted then it rewrites the term xaxis in the file consulting it or user’s session to the compound term vector(1, 0, 0).

But what I’m getting is: xaxis, no rewriting happening

If I understood correctly your question, one of the best answers should be the following.

@jan

term_expansion/2 is only called on the toplevel term. If you want to perform transformations inside the term you need to do so yourself. An intermediate step is provided by goal_expansion/2, which is called for each goal term in a clause.

Also note that term_expansion/2 is called only once per term, i.e., only the first answer of the expansion is used. goal_expansion/2 is called on the goal until fixed point is reached.