Hi there,
I have written a programme to compute a bootstrapped mean etc. I
successfully wrote it using lists both untyped and in typed/racket.
I am interested in optimising the code and having seen that typed racket
performs faster (for lists) I am interested in seeing if I get a
performance
Den lør. 15. feb. 2020 kl. 13.44 skrev greadey :
> I have written a programme to compute a bootstrapped mean etc. I
> successfully wrote it using lists both untyped and in typed/racket.
> I am interested in optimising the code and having seen that typed racket
> performs faster (for lists) I am
Did anyone suggest this code to you? Apologies if I’m re-treading an old
conversation.
#lang typed/racket
(: string2value (-> String Integer))
(define (string2value str)
(define maybe-integer (string->number str))
(cond [(exact-integer? maybe-integer) maybe-integer]
[else (error
Wait, we *all* have postmark libraries?
Sigh.
John
> On Jan 23, 2020, at 16:29, Jens Axel Søgaard wrote:
>
> Den tor. 23. jan. 2020 kl. 01.47 skrev Matthew Butterick :
> I concur on Postmark. For 2+ yrs I've used it with the Racket web server for
> mbtype.com. I pass the server settings to
On Sat, Feb 15, 2020 at 1:23 PM 'John Clements' via users-redirect <
us...@plt-scheme.org> wrote:
> Yes, absolutely. One reason that students in my class wind up using cast
> quite frequently in their parsers is that they use patterns like (list (?
> symbol s) …) which (as I recall) expand into
Yes, I’ll add this. It slightly increases the pain density, especially since I
think students likely to mistakenly write
(list (? symbol? #{s : Symbol}) …)
instead of the correct
(list (? symbol? #{s : (Listof Symbol)}) …)
… but it’s probably better than having to cast.
Thanks!
John
> On
Yes, absolutely. One reason that students in my class wind up using cast quite
frequently in their parsers is that they use patterns like (list (? symbol s)
…) which (as I recall) expand into unannotated lambda’s, and always require a
cast. I write that up here:
??
> (string2value "-1234")
- : Integer
-28766
> (string2value "abcd")
- : Integer
54562
>
Is this your desired behavior?
> On Feb 12, 2020, at 16:43, Alain De Vos wrote:
>
> I came to the following result as conversion function :
>
> #lang typed/racket
> (: string2value (-> String
Have you taken a look at How To Design Programs? At the end of section one, you
should have what you need to build these games and others like them:
https://htdp.org/2019-02-24/part_one.html
John Clements
> On Feb 3, 2020, at 03:31, Wilzoo wrote:
>
> Hi guys, so I am working on rolling dice
Belatedly: awesome, many thanks!
John
> On Jan 27, 2020, at 02:39, Sean Kemplay wrote:
>
>
> This is a good (free) course that takes you the lates best practices of JS
> (getting more functional), react and then react native.
>
>
For the record, this worked:
#lang typed/racket
(require typed/racket/class)
(define aninteger%
(class object%
(super-new)
(init-field [x : Integer 0])
(: getxinternal Integer)
(define getxinternal x)
(: getx (-> Integer))
(define/public (getx) getxinternal)))
When i try typed/racket :
#lang typed/racket
(define (integerclass x)
(define (getx) x)
(define (setx! [x_new : Integer]) (set! x x_new))
(define (add [y : integerclass]) : integerclass (integerclass (+ 1 (y
'getx
(lambda (message . args)
(case message
((getx) (apply
Following code makes an "integerclass" with an "add" method :
#lang racket
(define (integerclass x)
(define (getx) x)
(define (setx! x_new) (set! x x_new))
(define (add y)(integerclass (+ x (y 'getx
(lambda (message . args)
(case message
((getx) (apply getx
1. If the intention is to create a class, then I'd use the class form.
https://docs.racket-lang.org/reference/createclass.html#%28form._%28%28lib._racket%2Fprivate%2Fclass-internal..rkt%29._class%2A%29%29
Not that there's anything overtly wrong with using a closure, but common
validation tasks
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