Here's one way to write it in modern Racket:
#lang racket
(require (for-syntax syntax/parse))
(module+ test (require rackunit))
(define-syntax (my-and stx)
(syntax-parse stx
[(_) #'#f]
[(_ e:expr) #'e]
[(_ e1:expr e2:expr ...)
#'(if e1 (my-and e2 ...) #f)]))
(module+ test
(check-equal? (my-and) #f)
(check-equal? (my-and 1) 1)
(check-equal? (my-and 1 2) 2)
(check-equal? (my-and 1 #f 2) #f))
On Sun, May 9, 2021 at 9:30 AM Jens Axel Søgaard <[email protected]>
wrote:
> Hi Tim,
>
> In this case Ryan's method leads to:
>
>
> https://github.com/racket/racket/blob/master/racket/collects/racket/private/qq-and-or.rkt#L440
>
> But in case you are wondering about the style used in that file:
> at the point where "qq-and-or.rkt" is used, none of the usual
> syntax tools (such as syntax-case and syntax-parse) are available,
> so it is written using only primitive constructs.
>
> That is, that particular file does not represent the usual style of macro
> writing.
>
> /Jens Axel
>
>
> Den søn. 9. maj 2021 kl. 16.13 skrev Ryan Culpepper <
> [email protected]>:
>
>> Here are the three most convenient ways I know of to find that
>> information (which is "$RACKET/collects/racket/private/qq-and-or.rkt" in
>> this specific case):
>>
>> If you use DrRacket, then open a file that uses `and`, right-click on an
>> occurrence of `and`, and choose "Open Defining File" (which changes to
>> "Jump to Definition (in Other File)" once DrRacket opens the file.
>>
>> If you use Emacs with racket-mode, go to an occurrence of `and` and hit
>> "M-." (that is, hold down Meta/Alt and press the period key). You can also
>> use "M-x racket-visit-definition". That opens the defining module and jumps
>> to the definition.
>>
>> If you have the `whereis` package installed, run the command `raco
>> whereis -b racket/base and` and it will print the path of the defining file.
>>
>> Ryan
>>
>>
>> On Sun, May 9, 2021 at 3:26 PM Tim Meehan <[email protected]> wrote:
>>
>>> Where in the repository are macros like "and" and "or" defined?
>>> I tried searching for "and" and "or" ... but you probably know how that
>>> worked out.
>>>
>>> Thanks folks!
>>>
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>
>
> --
> --
> Jens Axel Søgaard
>
> --
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