Split out string utils.

src/util-string.scm

@@ -0,0 +1,83 @@
+;;
+;; util-string.scm
+;;
+;; Various string utilities.
+;;
+;; ISC License
+;;
+;; Copyright 2023 Brmlab, z.s.
+;; Dominik Pantůček <dominik.pantucek@trustica.cz>
+;;
+;; Permission to use, copy, modify, and/or distribute this software
+;; for any purpose with or without fee is hereby granted, provided
+;; that the above copyright notice and this permission notice appear
+;; in all copies.
+;; 
+;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+;; WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+;; WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+;; AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+;; CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+;; OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+;; NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+;; CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+;;
+
+(declare (unit util-string))
+
+(module
+ util-string
+ (
+  string-repeat
+  string-first+rest
+  )
+
+ (import scheme
+	 (chicken base)
+	 (chicken string)
+	 (chicken irregex)
+	 testing)
+
+  ;; Repeats given string.
+ (define (string-repeat str rep)
+   (let loop ((rep rep)
+	      (res '()))
+     (if (> rep 0)
+	 (loop (sub1 rep)
+	       (cons str res))
+	 (string-intersperse res ""))))
+
+ ;; Extracts first token and the rest as separate string
+ (define (string-first+rest str)
+   (let ((dm (irregex-search (irregex "[ \\t]" 'u) str)))
+     (if dm
+	 (let* ((sep-idx (irregex-match-start-index dm))
+		(key-str (substring str 0 sep-idx))
+		(sep+val (substring str sep-idx))
+		(val (irregex-replace (irregex "^[ \\t]*" 'u) sep+val "")))
+	   (cons key-str val))
+	 (cons str ""))))
+	 
+ ;; Performs utils module self-tests.
+ (define (utils-tests!)
+   (run-tests
+    utils
+    (test-equal? string-repeat
+		 (string-repeat "-" 4)
+		 "----")
+    (test-equal? string-repeat
+		 (string-repeat "š" 4)
+		 "šššš")
+    (test-equal? string-first+rest
+		 (string-first+rest "asdf rest")
+		 '("asdf" . "rest"))
+    (test-equal? string-first+rest
+		 (string-first+rest "asdf   rest test  rest")
+		 '("asdf" . "rest test  rest"))
+    (test-equal? string-first+rest
+		 (string-first+rest "asdf")
+		 '("asdf" . ""))
+    ))
+
+ )
+