I should have know better:
(define-syntax (set/define stx)
(syntax-case stx ()
[(_ id key val)
(identifier-binding #'id)
#`(begin
(hash-set! h 'key val)
h)]
[(_ id key val)
#'(begin
(define id (make-hash))
(set/define id key val))]))
This isn’t exactly what you refer to with “is unbound at run-time” in other
Lisps.
> On Apr 19, 2019, at 5:33 PM, zeRusski <vladilen.ko...@gmail.com> wrote:
>
> Not quite what I had in mind. The following examples must all work without
> errors:
>
> #lang racket
>
> ;; set/define defined here
>
> (set/define h a 1)
> (set/define h a 2)
> (hash-set! h 'b 42)
>
> (define bar (make-hash))
> (set/define bar a 1)
>
> (define (foo)
> (set/define local-h a 1)
> (set/define local-h a 2)
> (hash-set! local-h 'b 42)
> local-h)
>
> (foo)
>
> Basically, if the identifier h is unbound at runtime
> (set/define h key val)
> is the same as
> (define h (make-hash))
> (hash-set! h 'key val)
>
> If h is bound
> (hash-set! h 'key val)
>
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