Re: [racket-users] Time for draw-bitmap
2015-05-11 0:56 GMT+02:00 Matthew Flatt mfl...@cs.utah.edu: At Mon, 11 May 2015 00:30:05 +0200, Jens Axel Søgaard wrote: 2015-05-11 0:07 GMT+02:00 Matthew Flatt mfl...@cs.utah.edu: If you're on OS X, try creating the bitmap with (send canvas make-bitmap screen-width screen-height) instead of (make-object bitmap% screen-width screen-height) Roughly, using the `make-bitmap` method creates a bitmap that's on the graphics card instead of main memory. Two thoughts: - will make-screen-bitmap work too? No, only the `make-bitmap` method. See also http://docs.racket-lang.org/draw/overview.html#%28part._.Portability%29 Ok. - If I insert images in the teaching languages, do they become screen-bitmaps automatically? No, I don't think so. It's possible that it would make sense for `freeze` to use `make-bitmap`-method bitmaps. The `pict-pre-render-pict` function is similar to `freeze`, except that it's for picts in Slideshow, and it does use the `make-bitmap` method of Slideshow's canvas. (As you might guess, Slideshow was the original motivation for the feature.) I'm not certain that using a `make-bitmap` method would make as much sense even for `freeze`, since those images are less tied to a specific destination. Thanks. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Time for draw-bitmap
2015-05-11 2:24 GMT+02:00 Robby Findler ro...@eecs.northwestern.edu: But if you have a specific destination in mind you can make the bitmap first and then draw the 2htdp/image into it (or anything into it!) When I use my own game-loop it is easy enough to use the make-bitmap method of the canvas. I did see a significant improvement in responsiveness, so I thought maybe the same trick could be used in the implementation of big-bang. It's tricky though since the user produces the bitmaps, not the big-bang loop itself. FWIW: On OS X the difference between the two methods is so large the game went from unplayable to playable (due to a single call to draw-bitmap). I saw times between 7-9 milliseconds for the call. /Jens Axel -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Time for draw-bitmap
But if you have a specific destination in mind you can make the bitmap first and then draw the 2htdp/image into it (or anything into it!) Robby On Sunday, May 10, 2015, Matthew Flatt mfl...@cs.utah.edu wrote: At Mon, 11 May 2015 00:30:05 +0200, Jens Axel Søgaard wrote: 2015-05-11 0:07 GMT+02:00 Matthew Flatt mfl...@cs.utah.edu javascript:;: If you're on OS X, try creating the bitmap with (send canvas make-bitmap screen-width screen-height) instead of (make-object bitmap% screen-width screen-height) Roughly, using the `make-bitmap` method creates a bitmap that's on the graphics card instead of main memory. Two thoughts: - will make-screen-bitmap work too? No, only the `make-bitmap` method. See also http://docs.racket-lang.org/draw/overview.html#%28part._.Portability%29 - If I insert images in the teaching languages, do they become screen-bitmaps automatically? No, I don't think so. It's possible that it would make sense for `freeze` to use `make-bitmap`-method bitmaps. The `pict-pre-render-pict` function is similar to `freeze`, except that it's for picts in Slideshow, and it does use the `make-bitmap` method of Slideshow's canvas. (As you might guess, Slideshow was the original motivation for the feature.) I'm not certain that using a `make-bitmap` method would make as much sense even for `freeze`, since those images are less tied to a specific destination. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com javascript:;. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Environment Shuffling and 3D Syntax
I've fought my way a little up the hill, and enclosed is an implementation that I think works the way you want within a module. See the enclosed in-package.rkt. As you suspected, `make-syntax-introducer` is the piece that you need. In the terminology of the current macro expander, the function produced by `make-syntax-introducer` adds a mark to its argument syntax object. Each package has its own mark, and so a package's definitions are not visible outside the package (where references are missing the necessary mark to access the definition). To use the definitions of one package in another in an expression, `letrec-syntaxes` is wrapped around the expression to map the defined names of the used package to the names that are otherwise hidden by a mark. To make this strategy work, a package's definitions need to be detected, so `in-package` partially expands its body to detect `define-values`, etc. I can see a limitation of this implementation: In a package P that uses package Q, a macro defined in Q cannot expand to a definition in P. That's because the bindings of a used package can only be made available to expressions with the `letrec-syntaxes` wrapper, and that doesn't work for wrapping definitions. (A `splicing-letrec-syntaxes` wrapper doesn't work, because it interacts badly with the partial expansion needed to detect definitions.) As it turns out, we have an experimental variant of the Racket macro expander that can avoid the limitation. In the terminology of that expander, the function produced by `make-syntax-introducer` adds a scope to its argument syntax, and each package corresponds to a scope. Unlike marks, scopes on a syntax object are unordered, and so they can be added freely to access the content of used packages; no `letrec-syntaxes` wrapper is needed. I've included a set-of-scopes variant as in-package-scopes.rkt in case you're interested; you should be able to run it with a snapshot at http://www.cs.utah.edu/~mflatt/tmp/scope-snapshot/ For more information on the set-of-scopes expander, see http://www.cs.utah.edu/~mflatt/scope-sets-4/ At Fri, 8 May 2015 10:56:16 -0400, Philip Blair wrote: That's good to know about namespaces being intended to be for runtime reflection. I understand what you mean when you say bindings and lexical context, but in what specific way do you mean in the context of this issue? I also feel that I should mention that I am having difficulty wrapping my brain around is the utility of a couple of the functions listed in the documentation at http://docs.racket-lang.org/reference/stxtrans.html ; specifically, I am unsure what exactly internal definition contexts and syntax introducers are useful for. Lastly, as far as what I am attempting to implement, I am dabbling with trying to get at least a somewhat functional CL compatibility layer (I'm calling it `#lang clacket`) written. Since Lisp has s-expressions, I figured that there was no need to build a parser from scratch, but instead that I could bridge the gap between the two languages using syntax transformers. Things are going fairly well; I am just having issues getting this packages/identifier-binding issue sorted out. So, to specifically address your final paragraph, it looks like an uphill battle :) Any ideas? On Thu, May 7, 2015 at 2:33 PM, Matthew Flatt mfl...@cs.utah.edu wrote: I agree that those sound goals sound like a poor fit for `module+`. It's possible that `racket/package` provides something closer to the namespace-management tools that you need. Generally, I think you'll find more success by manipulating bindings and lexical context (in the sense of `datum-syntax`) instead of trying to use namespaces. Racket namespaces are intended more for run-time reflection; they're too dynamic for most code-organization tasks. I'm struggling to give more specific advice. If you need Common Lisp namespaces, I think that a close variant can be implemented in Racket, but it looks like an uphill battle. (Common Lisp is better at being Common Lisp; Racket is just better. :) Unless you're trying to run CL code with minimal modification, I'd encourage you to talk about your implementation goals, and maybe the list can offer ideas toward a suitable, Rackety abstraction. At Thu, 7 May 2015 07:29:48 -0700 (PDT), Philip Blair wrote: On Wednesday, May 6, 2015 at 11:02:33 PM UTC-4, Matthew Flatt wrote: I wonder whether whether expanding to `module+` might be a better direction. A rough expansion of your example might be #lang racket/base (module+ FOO (provide (all-defined-out)) (define BAR 2)) (module+ FOO (define BAZ (add1 BAR))) (module+ FOO (add1 BAZ)) (module+ QUUX (require (prefix-in FOO: (submod .. FOO))) (add1 FOO:BAZ)) ; = 4 (module+ main (require (submod .. FOO)) (require (submod .. QUUX))) where using
Re: [racket-users] [racket][off-topic] what's the official meaning of *.rktl and *.rktd?
.rktl is for files intended to be used with 'load', which is what the l stands for. .rktd is for files used with 'read', and the d stands for data. Sam On Sun, May 10, 2015, 9:40 PM WarGrey Gyoudmon Ju juzhenli...@gmail.com wrote: Sorry it's hard to find the official definition of **.rktl* and **.rktd* except both of them are racket source file extensions as well as **.rkt*. My dim memory shows that *l* means *load* or *link*? *d* means *D* *rRacket*? and these two ones are used for configuration. In my web htdocs, there are *servlet*.*rkt*, *literate-programming.**rkt * and *s-exp-configuration*.*rkt*. That would be great if they all have a conventional file extension instead of randomly choosing one on my own. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] [racket][off-topic] what's the official meaning of *.rktl and *.rktd?
Get it! Thank you Sam. On Mon, May 11, 2015 at 9:53 AM, Sam Tobin-Hochstadt sa...@cs.indiana.edu wrote: .rktl is for files intended to be used with 'load', which is what the l stands for. .rktd is for files used with 'read', and the d stands for data. Sam On Sun, May 10, 2015, 9:40 PM WarGrey Gyoudmon Ju juzhenli...@gmail.com wrote: Sorry it's hard to find the official definition of **.rktl* and **.rktd* except both of them are racket source file extensions as well as **.rkt*. My dim memory shows that *l* means *load* or *link*? *d* means *D* *rRacket*? and these two ones are used for configuration. In my web htdocs, there are *servlet*.*rkt*, *literate-programming.**rkt *and *s-exp-configuration*.*rkt*. That would be great if they all have a conventional file extension instead of randomly choosing one on my own. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[racket-users] racket on openwrt
Has anyone already made an OpenWRT `.ipk` package of Racket? Neil V. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] scribble namespace landgrab embedded package documentation
Matthew Flatt wrote on 05/07/2015 02:44 PM: I have no problem with these names --- the `scribble` exports are unlikely to ever collide, since we rarely resort to capital letters --- but I can't help thinking that the language of the metadata should specified explicitly. Regarding `#lang mcfly racket/base`, an additional reason I want to do three-semicolon comments is to *not* have each package depend on the documentation package. It's practically simpler sometimes. (I'm not the only one who doesn't fully like the dependency I had on the `mcfly` package; I've seen multiple other people copy my package code and strip out the McFly `doc` forms, so that they didn't have that dependency.) If someone else wants to put something other than embedded Scribble in three-semicolon comments, the fact that I'm using three-semicolon in a particular way won't break them, and they won't break me. Or, if someone in the future wants to scrape my three-semicolon stuff in the future, nothing's stopping them, and I'll even give them a small package to do that. I think I understand what you're saying about languages, but in this case, I'm pretty sure how I want to do this, and I'm comfortable with the longevity of the pragmatic simplifications right now. (Aside: I think the main advantage to the dependency on the `mcfly` PLaneT package was actually sneaky advertising or self-propagation. McFly is not a good example, but let's say there's a non-core package X that is used by various other packages. When a person uses a package that uses X, directly or indirectly, then documentation for X was added to the person's Racket documentation page, for them to stumble upon through documentation search and browsing. Then, the theory goes, that person is then more likely to add a new use of that package in packages that they write. So, if we get an ecology of lots of small packages using lots of small packages, and package X depends directly and indirectly on packages A, B, C, D, E, and F... the package X author doesn't even have to mention in documentation all those supporting packages (they often wouldn't even know all of the indirect ones), but the supporting packages still get a small bit of fame and propagation advantage each time. This is decentralized, with no authority declaring X to be a good package to do the things that X does, but just the little documentation-adding mechanism gives the memetics a boost.) Neil V. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Time for draw-bitmap
If you're on OS X, try creating the bitmap with (send canvas make-bitmap screen-width screen-height) instead of (make-object bitmap% screen-width screen-height) Roughly, using the `make-bitmap` method creates a bitmap that's on the graphics card instead of main memory. At Sun, 10 May 2015 23:14:08 +0200, Jens Axel Søgaard wrote: Hi All, The attached files are a work-in-progress. Eventually it will become a remake of Cees Kramer's Snoopy for C64. Anyways, the game represents an unmoveable object as a block structure. Today I decided to stop rendering the blocks for every frame. Instead they are rendered once to a background image, and then simply replace (send dc clear) with (send dc draw-bitmap the-background 0 0) in the game loop. To my surprise the frame rate dropped. It seems draw-bitmap is more expensive than I thought.? Or ... perhaps I am doing something that trips up draw-bitmap? Anyways, I have attached the game. To see the difference: Hold down the space bar. /Jens Axel -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Time for draw-bitmap
Worked like a charm. Thanks! 2015-05-11 0:07 GMT+02:00 Matthew Flatt mfl...@cs.utah.edu: If you're on OS X, try creating the bitmap with (send canvas make-bitmap screen-width screen-height) instead of (make-object bitmap% screen-width screen-height) Roughly, using the `make-bitmap` method creates a bitmap that's on the graphics card instead of main memory. At Sun, 10 May 2015 23:14:08 +0200, Jens Axel Søgaard wrote: Hi All, The attached files are a work-in-progress. Eventually it will become a remake of Cees Kramer's Snoopy for C64. Anyways, the game represents an unmoveable object as a block structure. Today I decided to stop rendering the blocks for every frame. Instead they are rendered once to a background image, and then simply replace (send dc clear) with (send dc draw-bitmap the-background 0 0) in the game loop. To my surprise the frame rate dropped. It seems draw-bitmap is more expensive than I thought.? Or ... perhaps I am doing something that trips up draw-bitmap? Anyways, I have attached the game. To see the difference: Hold down the space bar. /Jens Axel -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- Jens Axel Søgaard -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[racket-users] Time for draw-bitmap
Hi All, The attached files are a work-in-progress. Eventually it will become a remake of Cees Kramer's Snoopy for C64. Anyways, the game represents an unmoveable object as a block structure. Today I decided to stop rendering the blocks for every frame. Instead they are rendered once to a background image, and then simply replace (send dc clear) with (send dc draw-bitmap the-background 0 0) in the game loop. To my surprise the frame rate dropped. It seems draw-bitmap is more expensive than I thought.? Or ... perhaps I am doing something that trips up draw-bitmap? Anyways, I have attached the game. To see the difference: Hold down the space bar. /Jens Axel -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. snoopy.rkt Description: Binary data struct-utils.rkt Description: Binary data
Re: [racket-users] Time for draw-bitmap
2015-05-11 0:07 GMT+02:00 Matthew Flatt mfl...@cs.utah.edu: If you're on OS X, try creating the bitmap with (send canvas make-bitmap screen-width screen-height) instead of (make-object bitmap% screen-width screen-height) Roughly, using the `make-bitmap` method creates a bitmap that's on the graphics card instead of main memory. Two thoughts: - will make-screen-bitmap work too? - If I insert images in the teaching languages, do they become screen-bitmaps automatically? /Jens Axel -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Time for draw-bitmap
At Mon, 11 May 2015 00:30:05 +0200, Jens Axel Søgaard wrote: 2015-05-11 0:07 GMT+02:00 Matthew Flatt mfl...@cs.utah.edu: If you're on OS X, try creating the bitmap with (send canvas make-bitmap screen-width screen-height) instead of (make-object bitmap% screen-width screen-height) Roughly, using the `make-bitmap` method creates a bitmap that's on the graphics card instead of main memory. Two thoughts: - will make-screen-bitmap work too? No, only the `make-bitmap` method. See also http://docs.racket-lang.org/draw/overview.html#%28part._.Portability%29 - If I insert images in the teaching languages, do they become screen-bitmaps automatically? No, I don't think so. It's possible that it would make sense for `freeze` to use `make-bitmap`-method bitmaps. The `pict-pre-render-pict` function is similar to `freeze`, except that it's for picts in Slideshow, and it does use the `make-bitmap` method of Slideshow's canvas. (As you might guess, Slideshow was the original motivation for the feature.) I'm not certain that using a `make-bitmap` method would make as much sense even for `freeze`, since those images are less tied to a specific destination. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[racket-users] [racket][off-topic] what's the official meaning of *.rktl and *.rktd?
Sorry it's hard to find the official definition of **.rktl* and **.rktd* except both of them are racket source file extensions as well as **.rkt*. My dim memory shows that *l* means *load* or *link*? *d* means *D**rRacket*? and these two ones are used for configuration. In my web htdocs, there are *servlet*.*rkt*, *literate-programming.**rkt * and *s-exp-configuration*.*rkt*. That would be great if they all have a conventional file extension instead of randomly choosing one on my own. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Environment Shuffling and 3D Syntax
Probably off-topic: you might be interested in http://repository.readscheme.org/ftp/papers/sw2003/Scmxlate.pdf Start with the title and then the summary at the end. Dorai has used this package to make his programs available in Schemes and Common Lisps. -- Matthias On May 8, 2015, at 10:56 AM, Philip Blair wrote: That's good to know about namespaces being intended to be for runtime reflection. I understand what you mean when you say bindings and lexical context, but in what specific way do you mean in the context of this issue? I also feel that I should mention that I am having difficulty wrapping my brain around is the utility of a couple of the functions listed in the documentation at http://docs.racket-lang.org/reference/stxtrans.html ; specifically, I am unsure what exactly internal definition contexts and syntax introducers are useful for. Lastly, as far as what I am attempting to implement, I am dabbling with trying to get at least a somewhat functional CL compatibility layer (I'm calling it `#lang clacket`) written. Since Lisp has s-expressions, I figured that there was no need to build a parser from scratch, but instead that I could bridge the gap between the two languages using syntax transformers. Things are going fairly well; I am just having issues getting this packages/identifier-binding issue sorted out. So, to specifically address your final paragraph, it looks like an uphill battle :) Any ideas? On Thu, May 7, 2015 at 2:33 PM, Matthew Flatt mfl...@cs.utah.edu wrote: I agree that those sound goals sound like a poor fit for `module+`. It's possible that `racket/package` provides something closer to the namespace-management tools that you need. Generally, I think you'll find more success by manipulating bindings and lexical context (in the sense of `datum-syntax`) instead of trying to use namespaces. Racket namespaces are intended more for run-time reflection; they're too dynamic for most code-organization tasks. I'm struggling to give more specific advice. If you need Common Lisp namespaces, I think that a close variant can be implemented in Racket, but it looks like an uphill battle. (Common Lisp is better at being Common Lisp; Racket is just better. :) Unless you're trying to run CL code with minimal modification, I'd encourage you to talk about your implementation goals, and maybe the list can offer ideas toward a suitable, Rackety abstraction. At Thu, 7 May 2015 07:29:48 -0700 (PDT), Philip Blair wrote: On Wednesday, May 6, 2015 at 11:02:33 PM UTC-4, Matthew Flatt wrote: I wonder whether whether expanding to `module+` might be a better direction. A rough expansion of your example might be #lang racket/base (module+ FOO (provide (all-defined-out)) (define BAR 2)) (module+ FOO (define BAZ (add1 BAR))) (module+ FOO (add1 BAZ)) (module+ QUUX (require (prefix-in FOO: (submod .. FOO))) (add1 FOO:BAZ)) ; = 4 (module+ main (require (submod .. FOO)) (require (submod .. QUUX))) where using `module+` lets you splice together pieces of a submodule, and the final `main` submodule causes the others to be run. At Wed, 6 May 2015 16:04:59 -0700 (PDT), Philip Blair wrote: Hello, I am working on a project in which I am trying to implement a Common Lisp-style package system. A simple example of usage would be as follows: (in-package FOO (define BAR 2)) ; ... (in-package FOO (define BAZ (add1 BAR))) ; ... (in-package FOO (add1 BAZ)) ; = 4 ; ... (in-package QUUX (add1 FOO:BAZ)) ; = 4 I was able to get something to this effect by doing the following: 1. Create a namespace during phase 1 for each package 2. Wrap the (in-package ...) body in a submodule (to remove any local bindings in other parts of the file) 3. Wrap the body in the following: (require (for-syntax syntax/parse) racket/splicing) (parameterize ((current-namespace #,(package-namespace resolved-package))) (splicing-let-syntax ((#%top (λ(stx) (syntax-parse stx [(_ . id) #'(namespace-variable-value 'id)] #,@#'body)) This makes all non-local definitions resolve to the current namespace's definition. This works great. I ran into a problem, however, when trying to create a provide transformer for the packages. I wrote the transformer and tried to test it, only to be greeted by this message: write: cannot marshal value that is embedded in compiled code value The value in question was one of the namespaces I had created. Some searching online led me to http://stackoverflow.com/questions/17437037/what-is-3d-syntax , which,
[racket-users] testing with scope-set expander on Travis CI?
I want to test some of my packages on travis with the Matthew Flatt's scope-set expander. Right now I’m using Greg Hendershott’s way of setting up the .travis.yml, described here: http://www.greghendershott.com/2013/07/using-travis-ci-for-racket-projects.html I tried modifying that to support the scope-set snapshot here: https://github.com/AlexKnauth/travis-racket/tree/scope-set But testing that on travis fails with this error: https://travis-ci.org/AlexKnauth/travis-racket/jobs/61987612 Running ./racket-scope-snapshot.sh to install Racket: ./racket-scope-snapshot.sh: line 1: syntax error near unexpected token `newline' ./racket-scope-snapshot.sh: line 1: `?xml version=1.0 encoding=utf-8?' The command cat travis-racket/install-racket.sh | bash failed and exited with 2 during . Your build has been stopped. First, is there a better way, second, has anybody already done something like this, and third, if the answer to the first two were no, how do I get this to work? What am I doing wrong? -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
