Prolog: two or more

Question

Is there in prolog something like 'two or more' (or another option) to make the following shorter ?

rule(foo,  [bar,bar]). 
rule(foo,  [bar,bar,bar]).
rule(foo,  [bar,bar,bar,bar]).
rule(foo,  [bar,bar,bar,bar,bar]).

you can read it as: if there is a serie of n bars then assign the tag foo

This looks like "between 2 and 5 `bar`s". Do you really mean "one or more `bar`s"? — , Feb 19 '16 at 16:14
And altogether, attempt to write the question so that it is obvious what your problem is. — , Feb 19 '16 at 16:20

lurker · Accepted Answer · 2016-02-20T03:23:00.620

2

between/3 is probably what you're after:

rule(foo, L) :-
    between(2, 5, N),
    length(L, N),
    maplist(=(bar), L).

edited Feb 20 '16 at 03:23

answered Feb 19 '16 at 20:39

lurker

Yes! Thankyou, this is what i was looking for. – Brutalized Feb 20 '16 at 13:12
2

@Brutalized you are not supposed to change your question drastically. It invalidates the answers and comments given. Please change your question back and open a new question. But, if you give it some thought, you should be able to apply the technique I showed to solve that problem, too. – lurker Feb 20 '16 at 18:48

score 0 · Answer 2 · answered Feb 19 '16 at 18:00

0

This is a possibility

rule(foo, Out) :-
    random(2,6,N),
    length(Out,N),
    maplist(=(bar),Out).

answered Feb 19 '16 at 18:00

joel76

To get the behavior as in the OP's example, you probably want `between/3` not `random/3`. – lurker Feb 20 '16 at 03:42
Perhaps.The OP said **"i mean between 2 and 5"**. – joel76 Feb 20 '16 at 07:16

2 Answers2