2.7.2 library(explain): Describe Prolog Terms
library(explain) describes prolog-terms. The most
useful functionality is its cross-referencing function.
?- explain(subset(_,_)). "subset(_, _)" is a compound term from 2-th clause of lists:subset/2 Referenced from 46-th clause of prolog_xref:imported/3 Referenced from 68-th clause of prolog_xref:imported/3 lists:subset/2 is a predicate defined in /staff/jan/lib/pl-5.6.17/library/lists.pl:307 Referenced from 2-th clause of lists:subset/2 Possibly referenced from 2-th clause of lists:subset/2
Note that PceEmacs can jump to definitions and gxref/0 can be used for an overview of dependencies.
- Give an explanation on Term. The argument may be any Prolog
data object. If the argument is an atom, a term of the form
Name/Arityor a term of the form
Module:Name/Arity, explain/1 describes the predicate as well as possible references to it. See also gxref/0.
- [nondet]explain(@Term, -Explanation)
- True when Explanation is an explanation of Term.
The explaination is a list of elements that is printed using