Re: Does declaration order matter in guile?

[Dr. Arne Babenhauserheide]

Sascha Ziemann <ceving@gmail.com> writes:

> Am So., 12. Feb. 2023 um 20:52 Uhr schrieb Taylan Kammer
> <taylan.kammer@gmail.com>:
>>
>> On 12.02.2023 19:46, wolf wrote:
>>
>> > 1. When does order matter? What is going on here?
>>
>> The order matters in this case because the SRFI-9 implementation in Guile 
>> defines
>> syntax (macros) rather than just variables bound to procedures.
>
> This is a huge problem of Scheme in general, that you can not
> distinguish between
> procedures and macros just by looking at the code. You have to know it
> or you have
> to look it up in the manual.

I see this as a strength, because it allows me to start with a procedure
and switch it to be a macro later on if I need to.

That way I can start with the weaker but easier to reason about
construct and move to the stronger one when needed.

> You also can not ask Scheme about macros, because macros are not
> first-class-citizens.

Actually you can, though you need to take a detour through modules:

(define-syntax-rule (foo) #f)
(define (bar) #f)

(macro? (module-ref (current-module) 'foo))
;; => #t
(macro? (module-ref (current-module) 'bar))
;; => #f

(that’s from the info reference manual)

Best wishes,
Arne
-- 
Unpolitisch sein
heißt politisch sein,
ohne es zu merken.
draketo.de

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