Matthew can address the Racket internals questions, but one thing I'd
check, if you haven't already...
At the moment of the error, have all the free TCP ports on one of the
involved nodes been exhausted? You can probably check this on the
individual hosts close enough to the moment of the err
Stephen Bloch wrote at 06/29/2012 06:01 PM:
Either you introduce this stuff much better than I do, or your students are
much sharper.
For the possible benefit of any students reading, I think someone say
it, rather than leave it implied: Or the difference could be an isolated
effect of, say,
Hi there,
today's bug from hell might not be a Racket related issue (to me it seems more
of a Windows type of thing), but maybe somebody has already come across
something similar, so here goes:
I have a Racket application serving as a stress test against a TCP server, that
is, the Racket appli
>
>>
> make-person ; string string number -> person
> person-forename ; person -> string
>^
>|
>+-- please do notice the semicolon here; the rest of these
> lines are comments
>
> This will ensure he gets the names right.
Interesting idea
On Jun 29, 2012, at 10:34 PM, Matthias Felleisen wrote:
>
> On Jun 29, 2012, at 5:30 PM, Stephen Bloch wrote:
>
>> This is a fairly common confusion for my students
>
>
> This is the first time I am encountering this confusion.
Really? You've never had a student write a define-struct for
On Jun 29, 2012, at 5:52 PM, Stephen Bloch wrote:
> Another thing I recommend: every time you write a define-struct, write down
> (in comments) the contracts for all the functions it gives you for free.
>
> For example,
> ; a person has a forename and a family-name (both strings), and a birth-y
Another thing I recommend: every time you write a define-struct, write down (in
comments) the contracts for all the functions it gives you for free.
For example,
; a person has a forename and a family-name (both strings), and a birth-year (a
number).
(define-struct person forename family-name bi
On Jun 29, 2012, at 5:30 PM, Stephen Bloch wrote:
> This is a fairly common confusion for my students
This is the first time I am encountering this confusion.
Racket Users list:
http://lists.racket-lang.org/users
On Jun 29, 2012, at 9:12 PM, Roelof Wobben wrote:
> As I understand it Vanimal is the world which can exist of a Vcat or a Vcham.
> The problem is that I cannot know which one it is and if don't do a
> define-struct Vanimal () I cannot check if the make the right world.
Not true. You can check
Do pay attention to Vcat? and VCham?
On Jun 29, 2012, at 4:12 PM, Roelof Wobben wrote:
> I know.
> As I understand it Vanimal is the world which can exist of a Vcat or a Vcham.
> The problem is that I cannot know which one it is and if don't do a
> define-struct Vanimal () I cannot check if th
I know.
As I understand it Vanimal is the world which can exist of a Vcat or a
Vcham.
The problem is that I cannot know which one it is and if don't do a
define-struct Vanimal () I cannot check if the make the right world.
I will reread the chapter how to solve this.
Roelof
Op 29-6-2012 21:
On Jun 29, 2012, at 3:14 PM, Roelof Wobben wrote:
> ; Te gebruiken structs
>
> ; Design a world program that works with both cats and chameleons:
> ; A VAnimal is either
> ; – a VCat
> ; – a VCham
> (define-struct Vanimal (Vchat Vcham))
Please re-read the chapter. The above is completely wrong
Thanks for the remark.
I have now this as a solution :
; niet grafische constanten.
(define lengte-werkblad 200)
(define breedte-werkblad 1000)
(define move-animal 3)
(define move-gauge 0.1)
; grafische constanten
(define kat .)
(define cham .)
(define workspace (empty-scene breedte-werkbla
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 27-06-12 15:56, Matthias Felleisen wrote:
>
>
> 1. You got trapped in a strange corner of the language:
>
> -- to ask whether some value is a a Vcat you should use Vcat? --
> BSL should not really allow you to say 'Vcat' all by itself.
Actually
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