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Predicate term_string/3
Availability:built-in
Sourceterm_string(?Term, ?String, +Options)
As term_string/2, passing Options to either read_term/2 or write_term/2. For example: 
?- term_string(Term, 'a(A)', [variable_names(VNames)]).
Term = a(_9674),
VNames = ['A'=_9674].

Examples

Convert a string of 0s and 1s to an integer

Convert a string of 0s and 1s to an integer

This shows how to convert almost any "string" of 0s and 1s to an integer.

It takes advantage of the built-in term reading, thus avoiding an explicit loop and arithmetic.

binary_string_to_int(Str, Int) :-
    (   ( string(Str) ; atom(Str) )
    ->  atomics_to_string(["0b", Str], Literal)
    ;   is_list(Str)
    ->  atomics_to_string(["0b"|Str], Literal)
    ;   type_error(string_type, Str)
    ),
    catch(term_string(Int, Literal, []),
          error(syntax_error(_), _),
          type_error(string_of_0s_and_1s, Str)).
?- binary_string_to_int('101', X).
X = 5.

?- binary_string_to_int([0, 0, 1, 0, 1], X).
X = 5.

?- binary_string_to_int(["1", "1", "0"], X).
X = 6.
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Michael T. Richter said (2013-12-14T11:13:54):0 upvotes 0 0 downvotes
Picture of user Michael T. Richter.
This predicate doesn't appear to exist in v7.1.1. Some kind of comment needs to be put in the docs for predicates which have disappeared in the 6.6→7.1 changeover.