countall/2.

Ulrich Neumerkel (Version history)

p.p.x countall/2

p.p.x.1 Description

The following defines the procedural behaviour when no error conditions are satisified.

countall(G_0, N) :-
   findall(t, G_0, Ts),
   length(Ts, N).

p.p.x.2 Template and modes

p.p.x.3 Errors

a) G_0 is a variable
— instantiation_error.

b) G_0 is neither a variable nor a callable term
— type_error(callable, G_0).

c) N is neither a variable nor an integer
— type_error(integer, Nth).

d) N is an integer less than zero
— domain_error(not_less_than_zero, Nth).

e) The value of flag bounded is true and N is larger than max_integer
— evaluation_error(int_overflow).
—representation_error(max_integer).

p.p.x.4 Examples

?- countall((X=1;X=2), N).
   N = 2.
?- countall((true;true), N).
   N = 2.
?- countall(G_0, N).
   instantiation_error.
?- countall((length(L,5),nth0(_,L,_),nth0(_,L,_)), N).
   N = 25.
?- countall(N = 1, N).
   N = 1.
?- countall(N = non_integer, N).
   N = 1.
?- countall(false, 1).
   false.
?- countall(false, -1).
   domain_error(not_less_than_zero,-1).
?- countall(false, non_integer).
   type_error(integer,non_integer).

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