Nota Poin wrote on 11/08/2015 08:41 PM:
What I want is implicit keyword names for arguments with defaults. So
instead of:
(define (foo #:bar? (bar? #f) #:foo (foo 42) #:some-variable-name
(some-variable-name 3)) ...)
I'd like a variation on this. Since I (and lots of existing Racket
code) still use positional optional arguments sometimes, and since I'm
not sure I *always* want arguments (regardless of whether optional) to
have implicit keywords... I'd like simply a shorthand meaning "keyword
argument derived from argument variable name".
I haven't yet thought of a good backward-compatible syntax for this, but
two non-ideal ideas:
(define (bunny #(x) #(y) #(care-bears 1)) BODY ...)
(define (bunny #f x #f y #f (care-bears 1)) BODY ...)
Example uses:
(bunny :x 1 :y 2)
(bunny :x 3 :y 4 :care-bears 1000)
Note that, unlike some languages, I *don't* want `x` and `y` to be
optionally positional -- only keyworded. If I wanted positional
arguments, they'd be *only* positional, and not optionally keyworded.
Example:
(define (pony x y #(unicorn? #true)) BODY ...)
(pony 5 6)
(pony 5 6 :unicorn? #false)
(pony :x 7 8) ;=ERROR=> pony does not expect keyword argument `:x`
(pony 5 6 #false) ;=ERROR=> pony expects 2 positional arguments, not 3
Neil V.
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