/usr/share/Yap/stringutils.yap is in yap 6.2.2-6+b2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | :- module(string_utils,
[string/1,
upcase_string/2,
downcase_string/2,
string_length/2,
concat_strings/3
]).
:- use_module(library(lists),
[append/3]).
string([]).
string([A|Cs]) :-
integer(A),
A > 0, % no EOF allowed
A < 0x3ffffff, % UNICODE characters, strictly not yet required.
string(Cs).
upcase_string([], []).
upcase_string([C|Cs], [NC|NCs]) :-
code_type(C,to_lower(NC)),
upcase_string(Cs, NCs).
downcase_string([], []).
downcase_string([C|Cs], [NC|NCs]) :-
code_type(C,to_upper(NC)),
downcase_string(Cs, NCs).
string_length(S, Length) :-
length(S, Length).
concat_strings(S1, S2, New) :-
append(S1, S2, New).
|