Matthew Danish wrote:

> If you want to have some fun, why not write a nice higher-order function
> to do:
>
> (defun silly-loop (string &optional (increment 1) (final-char nil))
> (loop for n from 0 by increment
> for char across string
> until (eql char final-char)
> collect char into char-bag
> sum n into sum
> finally (return (values char-bag sum n))))
>
> Try to make it half as readable. And as efficient.

Gauche Scheme

(use gauche.sequence) ;; map [generic]

(define (silly str :optional (incr 1) (ender #f))
(let@ (0 n sum)
(values
(map (^(char) (inc! sum n) (inc! n incr) char)
(if ender
(car (string-split str ender))
str))
sum n)))

(silly "catch" 37 #\h)
===>
(#\c #\a #\t #\c)
222
148

(silly "catch")
===>
(#\c #\a #\t #\c #\h)
10
5

Given:

(define-syntax let@-aux
(syntax-rules ()
[(let@-aux (0 var ...) (pairs ...) stuff)
(let@-aux () (pairs ... (var 0) ...) stuff)]
[(let@-aux ('() var ...) (pairs ...) stuff)
(let@-aux () (pairs ... (var '()) ...) stuff)]
[(let@-aux (var val more ...) (pairs ...) stuff)
(let@-aux (more ...) (pairs ... (var val)) stuff)]
[(let@-aux (var) pairs stuff)
(let@-aux (var '()) pairs stuff)]
[(let@-aux () ((var val) ...) (stuff ...))
(let* ((var val) ...) stuff ...)]))
(define-syntax let@
(syntax-rules ()
[(let@ things stuff ...)
(let@-aux things () (stuff ...))]))