From 6a455d28665fb6288d5a1814ff422972b3fc05c5 Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Tue, 23 Aug 2022 19:54:11 +0200
Subject: [PATCH] ADDED: chars_si/1, testing for a string

Examples:

    ?- chars_si("hello").
       true.

    ?- chars_si(5).
       false.

    ?- chars_si([a,b,c|Rs]).
       error(instantiation_error,sort/2).
---
 src/lib/si.pl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/lib/si.pl b/src/lib/si.pl
index 173e2635..7fc3a596 100644
--- a/src/lib/si.pl
+++ b/src/lib/si.pl
@@ -27,7 +27,8 @@
 :- module(si, [atom_si/1,
                integer_si/1,
                atomic_si/1,
-               list_si/1]).
+               list_si/1,
+               chars_si/1]).
 
 :- use_module(library(lists)).
 
@@ -45,3 +46,7 @@ atomic_si(AC) :-
 list_si(L) :-
    \+ \+ length(L, _),
    sort(L, _).
+
+chars_si(Cs) :-
+   list_si(Cs),
+   '$is_partial_string'(Cs).
-- 
2.54.0