Option 2.  By the way have you though about the name call/kw (call with keywords) instead of keyword-call?

Marc

> On Nov 1, 2019, at 3:44 PM, Lassi Kortela <xxxxxx@lassi.io> wrote:
>
> Can we have a quick vote about who prefers the current option 1:
>
> (keyword-lambda (a b (c d e)) <lambda body ...>)
>
> (keyword-call foo 1 2 (e 5 c 3 d 4))
>
> And who would prefer option 2 where all of these are supported:
>
> (keyword-lambda (a b :key c d e) <lambda body ...>)
>
> (keyword-call foo 1 2 e: 5 c: 3 d: 4)     ; In all Schemes
> (keyword-call foo 1 2 :e 5 :c 3 :d 4)     ; In all Schemes
> (keyword-call foo 1 2 #:e 5 #:c 3 #:d 4)  ; In Schemes that have #:
>
> Option 1 can be implemented with syntax-rules and tail patterns.
>
> Option 2 needs syntax-case, explicit-renaming, or define-macro. It can be implemented equally well in Schemes that have native read syntax for keywords, and Schemes that don't. The trick is to treat a symbol starting or ending with a colon as a keyword.
>