Created the library random and moved some predicates from iso_ext

2020-04-26 23:33:10 +02:00
parent 3fd557c74a
commit de7a408903
2 changed files with 24 additions and 23 deletions
--- a/src/prolog/lib/random.pl
+++ b/src/prolog/lib/random.pl
@@ -0,0 +1,16 @@
+:- module(random, [maybe/0, set_random/1]).
+
+% succeeds with probability 0.5.
+maybe :- '$maybe'.
+
+set_random(Seed) :-
+    (   nonvar(Seed) ->
+        (  Seed = seed(S) ->
+        (  var(S) -> throw(error(instantiation_error, set_random/1))
+        ;  integer(S) -> '$set_seed'(S)
+        ;  throw(error(type_error(integer(S), set_random/1)))
+        )
+        )
+    ;   throw(error(instantiation_error, set_random/1))
+    ).
+