Hi,
For more context, please checkout:
https://issues.guix.gnu.org/issue/34999
On Tue, 24 Aug 2021 at 17:47, Leo Prikler <[email protected]> wrote:
> Am Dienstag, den 26.03.2019, 10:38 +0100 schrieb Ludovic Courtès:
>> The changes I made in version-control.scm and gnucash.scm in commit
>> e6301fb76d0a8d931ece2e18d197e3c2cc53fc6c revealed an abstraction
>> leakage
>> I wasn’t aware of: there’s a pattern where users “see” that thunked
>> fields are thunked:
>>
>> (package
>> ;; …
>> (inputs …)
>> (arguments `(foo bar ,(inputs) …))) ;<- here ‘inputs’ is seen as
>> a thunk
[...]
> #`(make-struct/no-tail type
> #,@(map (lambda (field index)
> - (or (field-inherited-value field)
> + (or (and=>
> + (field-inherited-value field)
> + (lambda (value)
> + (wrap-field-value field value)))
> (if (innate-field? field)
> (wrap-field-value
> field (field-default-value
> field))
For instance, this change is now irrelevant because of:
9b01a64e53b1f61ee13b62ac54cbefaf144e7d51
and c14b8636fbac9826115f4524d500536d54c15625
The current equivalent part reads:
(constructor-call
(map (lambda (field index)
(or (field-inherited-value field)
(if (innate-field? field)
(wrap-field-value
field (field-default-value field))
#`(struct-ref #,orig-record #,index))))
'(expected ...)
(iota (length '(expected ...))))))
and the ’and=>’ part could be still applied here, right?
About the two other parts of the patch, namely:
> @@ -211,8 +214,7 @@ of TYPE matches the expansion-time ABI."
> (map (lambda (field+value)
> (syntax-case field+value ()
> ((field value)
> - #`(field
> - #,(wrap-field-value #'field #'value)))))
> + #`(field value))))
> field+value))
>
> (syntax-case s (inherit expected ...)
> @@ -224,10 +226,11 @@ of TYPE matches the expansion-time ABI."
> ((_ (field value) (... ...))
> (let ((fields (map syntax->datum #'(field (... ...)))))
> (define (field-value f)
> - (or (find (lambda (x)
> - (eq? f (syntax->datum x)))
> - #'(field (... ...)))
> - (wrap-field-value f (field-default-value f))))
> + (wrap-field-value f
> + (or (find (lambda (x)
> + (eq? f (syntax->datum x)))
> + #'(field (... ...)))
> + (field-default-value f))))
>
> ;; Pass S to make sure source location info is preserved.
> (report-duplicate-field-specifier 'name s)
…I’ve not checked.
Well, the question is: What do we do with this patch? The bug is here
since so many years that now it might be considered as a feature. ;-)
WDYT?
Cheers,
simon
