> A `define-values` in a signature adds a definition to any *importing*
> context (in contrast to `define-values-for-export` which adds a
> definition in any *exporting* context). The `define-values/invoke-unit`
> form "imports" the signature into the definition context.
I reread the documentation
There is gls package https://github.com/Kalimehtar/gls/tree/master
It is even more generic (you may use any predicate as a `type')
Your case is
#lang racket
(require gls)
(defgeneric dup)
(add-method dup
(method ((a string?))
(string-append a a)))
(add-method dup
(method ((a exact
#lang racket
(require (for-syntax syntax/id-table))
(define-for-syntax table (make-free-id-table))
(define-syntax (save-and-define stx)
(syntax-case stx ()
[(_ ID) (free-id-table-set! table #'ID 1) #'(define ID 1)]))
(define-syntax (load stx)
(syntax-case stx ()
[(_ ID2)
(if (
On Apr 2, 2014, at 5:41 PM, Matthew Flatt wrote:
>>
>> What confuses me is that I can also define the following signature and unit:
>>
>> (define-signature y^
>> ((define-values (y) 5)))
>>
>> (define y@
>> (unit (import)
>>(export y^)))
>>
>> (define-values/invoke-unit y@ (import)
At Tue, 1 Apr 2014 02:29:17 -0400 (EDT), Daniel Feltey wrote:
> The define-signature form allows define-values and define-values-for-export
> forms in its body. According to the documentation the define-values form
> should
> prefix any unit that imports the signature, and define-values-for-expo
On 2014-04-02 20:53:58 +0200, Alejandro Zamora Fonseca wrote:
> ¿How can I create generic-functions in Racket?
>
> Something like
> this samples in CL:
>
> (defmethod dup ((a string))
> (concatenate 'string a a))
>
> (defmethod dup ((a integer))
> (list a a))
See the docs for the `racke
One of my students in lab today saw a Racket 6.0 core dump. Does this console
output ring a bell for anyone? Is this a bug that’s been fixed since the 6.0
release?
Many thanks,
John
Begin forwarded message:
> From: "Riley S. McGovern"
> Subject: Core Dump Log Error
> Date: April 2, 2014 at 1
Jay McCarthy writes:
> The package system currently doesn't use proxies at all. Howver, you
> should be able to go to
>
> https://github.com/jbclements/sxml/tarball/648a97f4881a8ea2f0959cf26e80bfdfec93d181
>
> in a web browser and download the archive manually then install it
> "raco pkg
On 02/04/2014 20:53, Alejandro Zamora Fonseca wrote:
(defmethod dup ((a string))
(concatenate 'string a a))
(defmethod dup ((a integer))
(list a a))
1) From the standard Racket "swindle/tiny-clos" library, you can use the
CLOS-like functions that you may already know from Common
Hello everybody!
I have a newbie question.
¿How can I create generic-functions in Racket?
Something like
this samples in CL:
(defmethod dup ((a string))
(concatenate 'string a a))
(defmethod dup ((a integer))
(list a a))
Cheers,
Alejandro
--
Este mensaje le ha llegado media
Hi Konrad,
The package system currently doesn't use proxies at all. Howver, you
should be able to go to
https://github.com/jbclements/sxml/tarball/648a97f4881a8ea2f0959cf26e80bfdfec93d181
in a web browser and download the archive manually then install it
"raco pkg install -n sxml the-file.tgz"
Is he giving a URL to DrRacket? If so could there be something operating at
the network layer (a proxy maybe) that gets in the way?
A simple thing to try is visit the URL in a browser, save the file and then
give DrRacket the path to the file (in that same dialog box).
Robby
On Wednesday, April
This semester I set up a handin server and all my students are using it
...except for one.
When he tries to install the prepared plt file via "Install .plt file",
DrRacket gives the complaint "gnu-gunzip bad header". Does anyone have a
pointer to what the problem might be?
He's using DrRacket v6.
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