Coming late to this.
On Wed, 14 Oct 2015 11:50:41 -0400, Neil Van Dyke
<n...@neilvandyke.org> wrote:
>We are conducting a highly scientific poll.
>
>The question we want to answer is whether people would like for the
>Racket standard languages to have symbols that begin with the colon
>character (except for the symbol `:`) to read the same has keywords that
>begin with pound-colon.
I actually prefer the #: syntax, but what I would like is support for
"existence" keywords - i.e. keywords with no argument - where the only
thing you care about is whether or not the keyword was provided.
Obviously, this can be done using a "rest" argument and symbols, but
the #: syntax draws attention that other symbols do not because
DrRacket, at least by default, colors keywords differently from other
symbols.
Although the keyword syntax coloring still works with a tick before a
symbol that looks like a keyword, having to remember the tick is a
PITA when you are thinking of the symbol as a keyword. If you forget
it, you get a nasty
"application: missing argument expression after keyword"
error.
How much trouble would it cause to allow naked keywords and provide a
predicate based on their name? E.g.,
(define ( test blah #:opt #:req req )
:
(when #:opt? ... )
:
)
(test #:req 3)
(test #:req 42 #:opt)
Or even something like (define ( test blah #:opt [] #:req req ) which
makes it more obvious that the keyword is only there to be tested?
George
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