more simplification

day01-easy/main.scm

@@ -44,12 +44,12 @@
 
 (define (sum numbers) (reduce numbers + 0))
 
+(define (is-numeric-char char) (if (char-numeric? char) #t #f))
+
 (define (solve-line line)
   (
     (lambda (first-last-result) (string->number (list->string first-last-result)))
-    (first-last
-      (string->list line)
-      (lambda (char) (if (char-numeric? char) #t #f)))))
+    (first-last (string->list line) is-numeric-char)))
 
 (define (solve-all lines)
   (sum (map lines solve-line)))