Solutions of some puzzles in Scheme (Lisp), my first experience with it.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 

60 lines
1.3 KiB

#!/usr/bin/guile -s
!#
(use-modules (ice-9 rdelim))
(define (read-lines)
(let loop ((line (read-line)))
(if
(eof-object? line)
'()
(cons line (loop (read-line))))))
(define (map list mapper)
(if
(null? list)
'()
(cons (mapper (car list)) (map (cdr list) mapper))))
(define (reduce list reducer current)
(if
(null? list)
current
(reduce (cdr list) reducer (reducer current (car list)))))
(define (combine list combiner)
(if
(null? (car list))
(cdr list)
(if
(null? (cdr list))
(car list)
(combiner (car list) (cdr list)))))
(define (sum numbers) (reduce numbers + 0))
(define (is-numeric-char char) (if (char-numeric? char) #t #f))
(define (first-last list predicate)
(if
(null? list)
'()
(combine
(cons
(if
(predicate (car list))
(cons (car list) (cons (car list) '()))
'())
(first-last (cdr list) predicate))
(lambda (current rest)
(cons (car current) (cdr rest))))))
(define (solve-line line)
(
(lambda (first-last-result) (string->number (list->string first-last-result)))
(first-last (string->list line) is-numeric-char)))
(define (solve-all lines)
(sum (map lines solve-line)))
(display (solve-all (read-lines)))