Procedure not found

[flexoron]

$ scryer-prolog -f
?- use_module(library(freeze)).
   true.
?- [user].
b(_,_,_).

?- freeze(X,Y=Z),freeze(Y,Y),bagof(Y=Y,X=Y,[Z=Z]),X=b(_,_,_).
   error(existence_error(procedure,b/3),b/3). % unexpected because:
?- b(1,2,3).
   true.
?- 

[flexoron]

Shorter

?- freeze(X,Y=X),freeze(Y,Y),X=b(_,_,_).
   error(existence_error(procedure,b/3),b/3).

Shortest

?- freeze(X,X),X=b(_,_,_).
   error(existence_error(procedure,b/3),b/3).

[UWN]

Shortester:

?- freeze(X,X).
   freeze:freeze(X,X).

Thus there is no clue, that X should be interpreted in module user and not in module freeze as in SICStus:

| ?- freeze(X,X).
prolog:freeze(X,user:X) ? 
yes

[triska]

Related: #2625.

[flexoron]

Why is this:

$ scryer-prolog -f
?- use_module(library(lists)).
   true.
?- use_module(library(freeze)).
   true.

?- [user].
:- module(b, [b/0]).
b:b.

?- freeze(X,X:X),X=b.
   X = b.
?- member(X,[b]).
   X = b.
?- freeze(X,X:X),member(X,[b]).
   error(type_error(callable,b:b),call/1). % what does it mean: callable?
?- call(b:b).
   true.
?- 

[UWN]

?- [X]=[b], b:X.
   X = b. % as expected
?- [X]=[b], X:b.
   error(type_error(callable,b:b),call/1), unexpected.

[UWN]

Related to partial strings, because

?- B=b,freeze(X,X:X),member(X,[B]).
   B = b, X = b. % as expected
?- freeze(X,X:X),[X]=[b].
   error(type_error(callable,b:b),call/1), unexpected.
?- [X]=[b], X:X.
   error(type_error(callable,b:b),call/1), unexpected.
?- asserta(t).
   true.
?- [X]=[t],X.
   X = t. % here, it seems to work

[flexoron]

$ rustc --version
rustc 1.83.0 (90b35a623 2024-11-26)
$ scryer-prolog -v
v0.9.4-210-gff034326

$ scryer-prolog -f
?- use_module(library(lists)).
?- use_module(library(lambda)).
?- [user]. f(x,y). end_of_file.

?- f(X,Y).
   X = x, Y = y.
?- call(f,A1,A2).
   A1 = x, A2 = y.
?- call(call(f, A1),A2).
   A1 = x, A2 = y.
?- call(f(A1),A2).
   A1 = x, A2 = y.

% lib/lambda.pl examples:

?- call(\X^f(X),A1,A2).
   error(existence_error(procedure,f/2),f/2). % unexpected
?- call(\X^Y^f(X,Y), A1,A2).
   error(existence_error(procedure,f/2),f/2). %    "
?- call(\X^(X+\Y^f(X,Y)), A1,A2).
   error(existence_error(procedure,f/2),f/2). %    "
?- 

The 'lib/lambda.pl' examples have been fixed with v0.9.4-215-gdba9c9a0
?- call(\X^(X+\Y^f(X,Y)), A1,A2).
   A1 = x, A2 = y.