This is my first try at making something like a make-keyword-procedure-
contract. Any suggestions or things I did wrong?
By the way it doesn't seem like a good idea to put separate contracts
on the kws and kw-args, but that's what I did for now because I don't
need to check anything about the
While your answer is what Manfred is looking for, I still find the original
behavior worrying. It lets you expose the internals of opaque data
structures without having the relevant inspector.
Sam
On Dec 28, 2013 4:16 PM, "J. Ian Johnson" wrote:
> You want to make sure your structs are inspectab
On Sat, 28 Dec 2013 17:15:25 -0500 (EST)
"J. Ian Johnson" wrote:
> You want to make sure your structs are inspectable. You can define
> your structs with the #:transparent option or define your own
> equality relation with the gen:equal+hash generic interface. -Ian
Aah, ok I got it. In my sourc
You want to make sure your structs are inspectable. You can define your structs
with the #:transparent option or define your own equality relation with the
gen:equal+hash generic interface.
-Ian
- Original Message -
From: Manfred Lotz
To: users@racket-lang.org
Sent: Sat, 28 Dec 2013 15:4
I just wrote a match-expander that does something like that:
(check-equal? (match 1 [(my-pat n:num) n]) 1)
(check-equal? (match 'x [(my-pat n:num) n] [_ 2]) 2)
like this:
#lang racket
(require rackunit)
(require (for-syntax
(only-in lang/htdp-intermediate-lambda
st
http://docs.racket-lang.org/reference/Building_New_Contract_Combinators.html?q=racketcontract
(But there is a new interface (the old one will continue to work of course)
in the git version)
Let me know if you have questions or get stuck and I'll try to improve the
docs.
Robby
On Sat, Dec 28, 2
What's the lower-level, projection-based api and how do I use it?
On Dec 28, 2013, at 11:50 AM, Robby Findler wrote:
I think you probably could make a contract that did what you were
talking about in the first message in this thread, but you cannot do
it with any of the existing contract com
I'm not sure why this works and that doesn't, but try passing n as an
argument to the match expander:
#lang racket
(require rackunit)
(define-match-expander num:
(λ(stx)
(syntax-case stx ()
[(num: n)
#'(? number? n)])))
(check-equal? (match 1 [(num: n) n]) 1)
(check-equal? (ma
I have a hash table (created by using make-hash) where the key is a
struct. This seems to work fine although the documentation says
The make-hash procedure creates a table where keys are compared with
equal?,...
and it seems that equal? gives #f if I compare two structs having the
same conte
Matthias,
I'm likely very misguided here and really just learning by hacking around,
so bare with me :).
I'm playing around with the idea of a sort of "Language Integrated Query"
like LINQ. For example:
> (sql (query 'my-table
#:where (λ (row) (> (hash-ref row 'id) 3
"select * from my-
I think you probably could make a contract that did what you were talking
about in the first message in this thread, but you cannot do it with any of
the existing contract combinators (->, ->*, case->, ->i, etc). You would
have to use the lower-level, projection-based api to make a new combinator.
We have also looked into the cause and are working to avoid this particular
failure mode.
We're sorry about this and are working to avoid it going forward.
Robby
On Sat, Dec 28, 2013 at 8:45 AM, Matthias Felleisen wrote:
>
> As some of you may have noticed, we experienced a day of downtime thi
1. I am stumped. I don't know how to write a contract for my-send.
2. I see what you want to do and I think you should seriously consider a
different protocol:
(define (get-vector this)
(vector (send this get-x) (send this get-y)))
For something like get-vector, I'd create a contract cons
As some of you may have noticed, we experienced a day of downtime this week.
It was due to a brief power outage and a slight misconfiguration of the server.
Eli will filter the mail queues so that messages about the outage are kept to
a minimum.
-- Matthias
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