#|kawa:1|# (define (foo #!rest args #!key a b c) (list 'args args 'a a 'b b 'c c))
#|kawa:3|# (foo a: 1 b: 2 c: 3)
(args (a: 1 b: 2 c: 3) a 1 b 2 c 3)
#|kawa:4|# (foo a: 1 b: 2 c: 3 d: 5)
(args (a: 1 b: 2 c: 3 d: 5) a 1 b 2 c 3)
#|kawa:7|# (apply foo (list a: 1 b: 2 c: 3))
(args (a: 1 b: 2 c: 3) a #f b #f c #f)
#|kawa:8|# (apply foo (arglist a: 1 b: 2 c: 3))
(args (a: 1 b: 2 c: 3) a 1 b 2 c 3)
#|kawa:14|# (define bar (arglist b: 2 c: 3))
#|kawa:16|# (apply foo (arglist a: 1 @:bar))
(args (a: 1 b: 2 c: 3) a 1 b 2 c 3)
#!allow-other-keys is not defined in DSSSL, but maybe that’s okay if we define #!rest first, see line 4.
The use of argilst and @:foo is a Kawa-ism that allows merging of keyword arguments. This is necessary when invoking a keyword function using apply, oftentimes make and friends.
The difference between list and arglist is shown in lines 7 and 8. For Kiwi, perhaps we could make it work for both lines?
#|kawa:3|# (define (test #!key (a 0) (b 1) (c 2)) (list a b c))
#|kawa:4|# (test)
(0 1 2)
Kawa does not support the 3-element form that Dylan accepts:
(define (test #key (a: _a 0) (b: _b 1) (c: _c 2)) (list _a _b _c))
but maybe that can be avoided.
I tried a similar thing with Gambit Scheme:
Gambit v4.9.5
> (define (foo #!rest args #!key a b c) (list 'args args 'a a 'b b 'c c))
> (foo a: 1 b: 2 c: 3 d: 5)
(args (a: 1 b: 2 c: 3 d: 5) a 1 b 2 c 3)
> (apply foo (list a: 1 b: 2 c: 3))
(args (a: 1 b: 2 c: 3) a 1 b 2 c 3)
> (apply foo (list a: 1 b: 2 c: 3 d: 4))
(args (a: 1 b: 2 c: 3 d: 4) a 1 b 2 c 3)
> (define bar (list b: 2 c: 3))
> (apply foo `(a: 1 ,@bar))
(args (a: 1 b: 2 c: 3) a 1 b 2 c 3)
> (apply foo (append (list a: 1) bar))
(args (a: 1 b: 2 c: 3) a 1 b 2 c 3)
Maybe this behavior is more desirable?