CODEWITHSUNDEEP
prologswi-prologpartial-applicationmaplist
sten
sten

Reputation: 7476

changing list of strings to atoms using maplist?

How to change string to atoms using maplist.

This does not work :

 ?- maplist(atom_string,["a","b","c"]).

first because atom_string/2 has arity of two (How do you do partial-function//currying in prolog).

But even if partial-fun worked the complication is that the first argument of atom_string is the unknown i.e. the call is :

  atom_string(A,"atom")

not :

  atom_string("atom",A)

this worked :

?- use_module(library(lambda)).

?- F = \Y^X^(atom_string(X,Y)), maplist(F,["a","b","c"],L).
F = \Y^X^atom_string(X, Y),
L = [a, b, c].

Upvotes: 1

Views: 423

Answers (2)

TA_intern
TA_intern

Reputation: 2436

This works as intended:

?- maplist(atom_string, Atoms, ["a","b","c"]).
Atoms = [a, b, c].

If this is not what you are after, please explain.

Upvotes: 3

Guy Coder
Guy Coder

Reputation: 24976

Use a helper predicate.

string_atom(String,Atom) :-
    atom_string(Atom,String).

Then run using

?- maplist(string_atom,["a","b","c"],Atoms).
Atoms = [a, b, c].

Upvotes: 1

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