[racket-users] Re: mred/12252: DrRacket Fails to Quit at Logout

2015-05-20 Thread Michael Tiedtke
Il giorno 20/mag/2015, alle ore 16.44, Matthew Flatt ha scritto: > It's been a few years since I last looked at this. If I remember > correctly, the problem is a mismatch between the `racket/gui` model of > eventspaces and the way that shutdown notifications and responses work > in Cocoa. The mis

Re: [racket-users] Doing pattern matching by reader macro

2015-05-20 Thread Alexander D. Knauth
Here’s one way to do something like that with a macro: https://github.com/AlexKnauth/define-match-spread-out/blob/master/define-match-spread-out/main.rkt And using it: https://github.com/AlexKnauth/define-match-spread-out/blob/master/define-match-spread-out/tests/test.rkt On May 18, 2015, at 9:39

Re: [racket-users] Re: Specifying a contract for the end of a list

2015-05-20 Thread Alexander D. Knauth
Would an append/c combinator be a good generalization of this? I’ve already made an append/c combinator that works with just flat-contracts, but is there a good way to make it work for chaperone contracts? https://github.com/AlexKnauth/match-string/blob/master/match-string/main.rkt#L205 http://p

[racket-users] Re: Specifying a contract for the end of a list

2015-05-20 Thread Philip Blair
On Tuesday, May 19, 2015 at 12:23:34 AM UTC-4, Alexis King wrote: > I've recently wanted a contract that lets me check the last element of a > (potentially improper) list, ignoring the other elements. To do this in a > general sense, I came up with this. > > (define (listof* init/c last/c) > (

Re: [racket-users] Racket should not cancel an OS shutdown

2015-05-20 Thread Michael Tiedtke
Thank you very much!! Returning "NSTerminateNow" in the handler works fine me ... Il giorno 20/mag/2015, alle ore 16.44, Matthew Flatt ha scritto: > It's been a few years since I last looked at this. If I remember > correctly, the problem is a mismatch between the `racket/gui` model of > events

[racket-users] Scribble form for a documentation redirect?

2015-05-20 Thread Matthew Butterick
Suppose module foo provides `bar`, and module zam requires foo and also provides `bar` from foo. Further suppose that foo contains the main documentation for `bar`. When writing Scribble docs, I've noticed that `(require (for-label ...))` seems to resolve exported-name conflicts in favor of the

Re: [racket-users] How to fill a shape with a texture using 2htdp/image or similar?

2015-05-20 Thread Robby Findler
2htdp/image doesn't support that now, but the "color" argument of various functions there could be generalized to support a new "brush" struct (in the way that pen structs work for outline images) that had a bitmap field to do what you want. The internal helper function mode-color->brush would have

[racket-users] Re: [racket][web] How to make security-guard work with servlets

2015-05-20 Thread WarGrey Gyoudmon Ju
On Wed, May 20, 2015 at 7:09 PM, Jay McCarthy wrote: > The Racket feature of a 'security guard' is not what you want, I > think. It prevents a block of Racket code from doing things like > accessing the file system or the network. It is used, for example, by > evaluation sandboxes to protect agai

[racket-users] How to fill a shape with a texture using 2htdp/image or similar?

2015-05-20 Thread Daniel Prager
2htdp/image makes it easy to draw all sorts of solid shapes (triangles, squares, stars, etc.) and fill them with a solid color. But say I want to fill with a texture (say from a bitmap loaded from a file). I could brute-force it by creating a separate stencil image, converting both to pixels and c

[racket-users] [racket][web] How to make security-guard work with servlets

2015-05-20 Thread WarGrey Gyoudmon Ju
Hello Jay, and Racketeers. What the original problem is: I want my pure Racket Web Server listens on port 80, and this server allows per-user dynamic content. As a security problem, no comprehensive solutions exists, it is a big topic of system administration. In real world, the racket web serv

Re: [racket-users] Racket should not cancel an OS shutdown

2015-05-20 Thread Matthew Flatt
It's been a few years since I last looked at this. If I remember correctly, the problem is a mismatch between the `racket/gui` model of eventspaces and the way that shutdown notifications and responses work in Cocoa. The mismatch makes it difficult for `racket/gui` to defer its answer to the OS whi

Re: [racket-users] RACO : how to build a shared fPIC library?

2015-05-20 Thread DEGAT Yann
the way osv.io works : the system doesn't have a userspace. there's a single memory address space in which the system boots, and at the end of the init, the only OS process makes a call to the "main" function of the shared library that has been added to the system. it's not able to spawn any new pr

Re: [racket-users] RACO : how to build a shared fPIC library?

2015-05-20 Thread Matthew Flatt
As you say, you can build the Racket executable using shared libraries by configuring with `--enable-shared`. Then, when you create an executable with `raco exe`, you end up with a smaller executable that refers to the shared libraries. I'm not sure how much that will save, since an executable cre

Re: [racket-users] Re: Implementing a lazy for/stream using for/fold/derived and delimited control

2015-05-20 Thread Matthew Flatt
At Tue, 19 May 2015 20:33:57 -0700, Alexis King wrote: > As I've continued to experiment with this, I've run into something that I > don't > really understand. I've managed to come up with this snippet of code. > > (define (do prompt-tag) > (define (loop element continue) > (if continue >

Re: [racket-users] Storing functions in a hash

2015-05-20 Thread Norman Gray
j b, hello. Depending on what this is a cut-down version of, I think you may have slightly over-engineered it. > On 2015 May 20, at 13:41, j b wrote: > > ; function definition helper > (define-syntax-rule (define-hash-function f p ...) > (define (f) (lambda () p ...))) This defines f to be

Re: [racket-users] Storing functions in a hash

2015-05-20 Thread Matthias Felleisen
Yes, this is over-engineered. What do you not like about (define h1 (hash 'foo (lambda () (random 100)) 'bar (lambda () (random 500 (displayln h1) (displayln ((hash-ref h1 'foo))) (displayln ((hash-ref h1 'foo))) (displayln ((hash-ref h1 'bar))) (displayln ((hash-ref h1 'bar))) Onc

[racket-users] Storing functions in a hash

2015-05-20 Thread j b
I'm new to Racket/Scheme/Lisp. In addition to learning how to use the language, I also want to do it the "Racket way". I am trying to put functions into a hash so I could call them using a hash key lookup (I just use 'random' as a filler in this example for what I really want. I have it worki

[racket-users] Re: [racket][web] How to make security-guard work with servlets

2015-05-20 Thread Jay McCarthy
The Racket feature of a 'security guard' is not what you want, I think. It prevents a block of Racket code from doing things like accessing the file system or the network. It is used, for example, by evaluation sandboxes to protect against un-trusted user code. I don't think you want to run your co

[racket-users] "Systematic Program Design" by Gregor Kiczales on edx.org

2015-05-20 Thread Stefan Schmiedl
Gregor Kiczales is offering a course on Systematic Program Design (https://www.edx.org/course/systematic-program-design-part-1-core-ubcx-spd1x) starting June 2. It promises to be an extended and improved reincarnation (three! parts) of the coursera offering. Racket (with various Student Languag

Re: [racket-users] Implementing a lazy for/stream using for/fold/derived and delimited control

2015-05-20 Thread Alexis King
I've never particularly loved racket/generator's interface, but you're right that it could be a useful base for this sort of abstraction. I do explicitly want a stream, but I could use in-generator in tandem with sequence->stream to get that. That said, I would still be interested in figuring o