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Minerva offers 2 built-in predicates for function style evaluation of built-in and user defined predicates.
is/2 arithmetic evaluation <-/2 function evaluation
Programming with functions is sometimes easier to write and read than the equivalent predicate.
You can define an arithmetic function with a predicate that returns its value in the last argument
somearithmetic(Arg1,...,ArgN,Result)and call it either in relational notation with
?- somearithmetic(Arg1,...,ArgN,Result)or in functional notation with
?- Result is somearithmetic(Arg1,...,ArgN).
You can define a general function with a predicate that returns its value in the last argument
Predicate(Arg1,...,ArgN,Result)and call it either in relational notation with
?- Predicate(Arg1,...,ArgN,Result)or in functional notation with
?- Result <- Predicate(Arg1,...,ArgN).
<-/2 behaves as defined like
Res <- Goal :- Goal =.. [Name|Args], append(Args,[Res],XtArgs), XtGoal =.. [Name|XtArgs], call(XtGoal).
but is/2 and <-/2 are efficiently implemented builtin predicates of MINERVA.
Example with classic Prolog:
List <- append([a,b,c],[d,e,f])
Example with a MINERVA Object:
Counter <- create_counter(10), Index <- Counter::next, ...
| document: http://www.ifcomputer.co.jp/MINERVA/Manual/Reference/Functions/print_de.html published 2008/11/17 update 2003/2/28 (c) 1996-2006 IF Computer Japan | ||||||||
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