Example
Here is a piece of Prolog code:
girl(sally). girl(jane). boy(B) :- \+ girl(B).A WAM-based Prolog compiler will compile this into WAM instructions similar to the following:
predicate(girl/1): switch_on_term(2,1,fail,fail,fail), label(1): switch_on_atom label(2): try_me_else(4) label(3): get_atom(sally,0) proceed label(4): trust_me_else_fail label(5): get_atom(jane,0) proceed predicate(boy/1): get_variable(x(1),0) put_structure(girl/1,0) unify_local_value(x(1)) execute((\+)/1)])An important characteristic of this code is its ability to cope with the various modes in which the predicates can be evoked: Any argument might be a variable, a ground term, or a partly instantiated term. The "switch" instructions handle the different cases.
Read more about this topic: Warren Abstract Machine
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