Data commit

Task/Palindrome-detection/Ol/palindrome-detection.ol

@@ -0,0 +1,27 @@
+; simple case - only lowercase letters
+(define (palindrome? str)
+   (let ((l (string->runes str)))
+      (equal? l (reverse l))))
+
+(print (palindrome? "ingirumimusnocteetconsumimurigni"))
+; ==> #true
+(print (palindrome? "thisisnotapalindrome"))
+; ==> #false
+
+
+; complex case - with ignoring letter case and punctuation
+(define (alpha? x)
+   (<= #\a x #\z))
+(define (lowercase x)
+   (if (<= #\A x #\Z)
+      (- x (- #\A #\a))
+      x))
+
+(define (palindrome? str)
+   (let ((l (filter alpha? (map lowercase (string->runes str)))))
+      (equal? l (reverse l))))
+
+(print (palindrome? "A man, a plan, a cat, a ham, a yak, a yam, a hat, a canal-Panama!"))
+; ==> #true
+(print (palindrome? "This is not a palindrome"))
+; ==> #false