Re: [racket-users] [racket users] struct #:methods question

[David Storrs]

On Mon, Apr 20, 2020 at 6:50 PM Jon Zeppieri  wrote:

> There's no trick to it:
>
> #lang racket/base
>
> (require racket/generic)
>
> (define-generics foo
>   (foo-do foo x))
>
> (struct thing (x)
>   #:methods gen:foo
>   [(define (foo-do f x)
>  (thing x))])
>
>
> On Mon, Apr 20, 2020 at 6:32 PM Kevin Forchione  wrote:
> >
> > Hi guys,
> > How do you return an instance of the structure type from the struct’s
> #:methods? This is would seem to be a common situation, but it has me
> stumped.
> >
> > Kevin
>



Note that if you're getting fancy with structs then you might want to check
out: https://docs.racket-lang.org/struct-plus-plus/index.html

Among other things, it auto-generates functional setters and functional
updaters, a keyword constructor, dotted accessors, reflection data, and
allows for contracts on individual fields and enforcement of relationships
between fields.



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Re: [racket-users] [racket users] struct #:methods question

[Jon Zeppieri]

There's no trick to it:

#lang racket/base

(require racket/generic)

(define-generics foo
  (foo-do foo x))

(struct thing (x)
  #:methods gen:foo
  [(define (foo-do f x)
 (thing x))])


On Mon, Apr 20, 2020 at 6:32 PM Kevin Forchione  wrote:
>
> Hi guys,
> How do you return an instance of the structure type from the struct’s 
> #:methods? This is would seem to be a common situation, but it has me stumped.
>
> Kevin
>
> --
> You received this message because you are subscribed to the Google Groups 
> "Racket Users" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to racket-users+unsubscr...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/racket-users/EE404363-995C-4888-8B43-E463EB3C7418%40gmail.com.

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[racket-users] [racket users] struct #:methods question

[Kevin Forchione]

Hi guys,
How do you return an instance of the structure type from the struct’s 
#:methods? This is would seem to be a common situation, but it has me stumped.

Kevin

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