2.3 Online Help

Online help provides a fast lookup and browsing facility to this manual. The online manual can show predicate definitions as well as entire sections of the manual.

help

Equivalent to help(help/1).

help(+What)

Show specified part of the manual. What is one of:

<Name>/<Arity>	give help on specified predicate
<Name>	give help on named predicate with any arity or C interface function with that name
<Section>	display specified section. section numbers are dash-separated numbers:2-3refers to section 2.3 of the manual. Section numbers are obtained usingapropos/1.

Examples

?- help(assert).	give help on predicate assert
?- help(3-4).	display section 3.4 of the manual
?- help('PL_retry').	give help on interface function PL_retry()

apropos(+Pattern)

Display all predicates, functions and sections that have Pattern in their name or summary description. Lowercase letters in Pattern also match a corresponding uppercase letter. Example:

?- apropos(file).

Display predicates, functions and sections that have `file' (or `File', etc.) in their summary description.

explain(+ToExplain)

Give an explanation on the given `object'. The argument may be any Prolog data object. If the argument is an atom, a term of the form Name/Arity or a term of the form Module:Name/Arity, explain will try to explain the predicate as well as possible references to it.

explain(+ToExplain, -Explanation)

Unify Explanation with an explanation for ToExplain. Backtracking yields further explanations.