Answer Sources :: Code docs

Part of Nan.System.Sources (nan/system/sources.pl)

We conform to SWI-Prolog Source Documentation Version 2 [*], except for argument instantiation modes and relative meanings, as detailed in section Predicate documentation.

[*] http://www.swi-prolog.org/pldoc/package/pldoc.html

Predicate documentation

The header of the documentation of a predicate consists of one or more templates, each defining a specific way of calling the predicate:

<template>       ::= <head>['//'] 'is' <determinism> | <head>['//']
<determinism>    ::= 'det' | 'semidet' | 'failure' | 'nondet' | 'multi'
<head>           ::= <functor>'('<args>')' | <functor>
<args>           ::= <argspec>',' <args> | <argspec>
<argspec>        ::= [<instantiation>]<argname>[':'<type>]
<instantiation>  ::= '+' | '-' | '?' | ':' | '@' | '!'
<type>           ::= <term>

The meaning of the determinism modes is:

Determinism	Predicate behaviour
`det`	Succeeds exactly once.
`semidet`	Fails or succeeds exactly once.
`failure`	Always fails.
`nondet`	Fails or succeeds one or more times.
`multi`	Succeeds one or more times.

The meaning of the argument instantiation modes is:

Instantiation	Direction	Argument requirements
`+`	Input argument	Must satisfy type at call time. May be instantiated further.
`-`	Output argument	Must be unbound at call time. Will satisfy type on exit.
`?`	Output argument	As `-` but "steadfast". (With `nonvar` argument, `det` becomes `semidet`, etc.)
`:`	Input argument	As `+` but treated as a meta-argument.
`@`	Input argument	As `+` but not instantiated further.
`!`	Input argument	As `+` but may be modified destructively.

NOTE: The result of calling a predicate with incorrectly instantiated arguments is undefined and may include errors and unexpected behavior.

author: - Julio P. Di Egidio
version: - 1.2.0-beta
license: - GNU GPLv3