gmane.lisp.scheme.plt

Web Application

Rohan Golwala — 2008-12-01T21:20:48

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abstracting over (PLaneT) requires

Rob Hunter — 2008-12-01T18:38:42

Is there any way to abstract over requires? In particular, I'm interested in abstracting over the version of a PLaneT package that I require. Something like (require (planet "some-file.ss" ("joe" "a-package.plt" MAJOR (= MINOR)))) where MAJOR and MINOR could be bound in exactly one spot. Thus, I could easily do a system-wide change of which version of a-package.plt I am including. Thanks! Rob _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

R: Unexpected error using "static-files-path"

Ferreira Maurizio — 2008-12-01T15:37:58

Noel Welsh wrote: have the latest version (including the minor version number). I'm triyng with a fresh installation of Plt scheme 4.1.3 [3m], under windows 2000. The problem still persists. Regards Maurizio. _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

PEPM'09 -- Call for Participation

G. Puebla and G. Vidal — 2008-11-30T23:07:20

ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation (PEPM'09) January 19-20, 2009 Savannah, Georgia, USA http://clip.dia.fi.upm.es/Conferences/PEPM09 CALL FOR PARTICIPATION IMPORTANT DATES * Hotel reservation deadline: December 18, 2008 * Early registration deadline: December 19, 2008 VENUE PEPM'09 and all POPL'09 affiliated events will take place at the Hyatt Regency Savannah hotel. SCOPE The PEPM Symposium/Workshop series aims at bringing together researchers and practitioners working in the areas of program manipulation, partial evaluation, and program generation. PEPM focuses on techniques, theory, tools, and

Unexpected error using "static-files-path"

Ferreira Maurizio — 2008-12-01T09:48:07

I tried the following example, taken from the tutorial "Continue: Web Applications in PLT Scheme " As i start the program I receive the following error: procedure application: procedure: #; does not expect an argument with keyword #:extra-files-path; arguments were: # #:extra-files-path # #:launch-browser? #t Any suggestion ? Regards Maurizio. #lang web-server/insta (define (start request) '(html (head (title "Testing")) (link ((rel "stylesheet") (href "/test-static.css") (type "text/css"))) (body (h1 "Testing") (h2 "This is a header") (p "This is " (span ((class "hot")) "hot") ".")))) (static-files-path "htdocs") _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Setup and teardown in SchemeUnit

Michał Kwiatkowski — 2008-11-30T22:05:31

Hi, I'm looking for something along the lines of setup and teardown methods, as implemented in most xUnit frameworks. They run before and after each test case belonging to given test suite. Is that functionality available in SchemeUnit? In documentation I've only found "before" and "after" procedures of the test-suite, but those run only once for the whole suite. Cheers, mk _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

scroll bars on definition window

Jon Rafkind — 2008-11-30T08:57:14

I'd like to be able to adjust the scrollbars programmatically via set-scroll-pos/get-scroll-pos in Drscheme but I cannot find the proper canvas to use. If I call `get-canvas' on the current tab thing I get a definitions-canvas% back which apparently doesn't extend canvas%. How can I get the object that controls the scrollbars on the definitions window? _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Help intigrating C/C++ into Scheme

Zukowski, Steven D — 2008-11-29T21:59:10

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trapping key events in text-field%

Gregory Cooper — 2008-11-29T19:53:04

Hi, What's the right way to catch key events in a text-field%? I thought I should override its on-subwindow-char, but that seems to catch each event twice. E.g., if I run the following program and type "a" into the text field, it displays: 1: a 2: a 3: release 4: release If I remove the (super ...) call, I get: 1: a 2: release but then the "a" doesn't appear in the text field. Thanks, Greg ------- (require mred/mred) (require scheme/class) (define frame (new frame% [label "Example"] [min-width 640])) (define input (new (class text-field% (super-new) (define count 0) (define/override (on-subwindow-char t e) (set! count (add1 count)) (printf "~a: ~a~n" count (send e get-key-code)) (super on-subwindow-char t e))) [parent frame] [label ""])) (send frame show #t) _________________________________

Minor difference Apple v Windows versions

wooks — 2008-11-29T10:16:05

Recently did a demo of a PLT application on a Mac (just downloaded) version of Dr Scheme. Mac version complained about 2 definition names (identity and compose) that run fine on the windows version. _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Snooze and application-level validation beforepersisting

Peter Michaux — 2008-11-28T20:25:05

I've been looking at the Snooze documentation http://planet.plt-scheme.org/package-source/untyped/snooze.plt/2/2/planet-docs/snooze/index.html I don't see anything about validating data before attempting to persist it to the database. I'm curious about how a programmer using Snooze would go about validating in the application. If there is invalid data, how does the model layer then either throw errors or return an errors object rather than attempting to persist the data. I'm thinking of a web application where the errors then need to be displayed to the user in an HTML form but this is not really a web-specific issue. Thanks, Peter _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Serializing/deserializing in a servlet

Eddie Sullivan — 2008-11-28T19:45:41

Hi. The following simple code works well normally, but when run in a servlet causes a strange error: #lang scheme (require scheme/serialize web-server/servlet-env) (define-serializable-struct test-struct (a)) (define (test-serialize) (let* ([s (make-test-struct "Eddie Sullivan")] [serialized-s (serialize s)] [new-s (deserialize serialized-s)]) (display (format "test-serialize: Saved a: ~a" (test-struct-a new-s))))) (define (go) (serve/servlet start)) (define (start request) (test-serialize)) In DrScheme (Windows, vs 4.1.3), if I call (test-serialize), I see the expected result: test-serialize: Saved a: Eddie Sullivan On the other hand, if I call (go), I see the following error: Servlet (< at > /servlets/standalone.ss) exception: test-struct-a: expects args of type ; given instance of a different Any tips? Thanks. -Eddie Sullivan ________________________

nonstandard installation

Prabhakar Ragde — 2008-11-28T16:28:06

We have a heterogenous network of mostly Solaris servers for undergraduate computing. Our sysadmins use a locally-brewed software distribution system which involves building on one machine and pushing files to other machines. Thus their installation of PLT Scheme will not run setup-plt on a destination machine (except the build machine). I asked a tutor to build a copy of PLT Scheme from scratch in their local account, and in running a trivial program, the "user time" of the local mzscheme is twice as fast as the officially-installed version. What might cause this problem, and what can I suggest to the sysadmins to fix it that might be consistent with the way they do things? Thanks. --PR _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

BNF in slideshow

Paulo J. Matos — 2008-11-27T20:16:37

Hi, Has anybody used slideshow to present BNF rules? Is yes, what's the best way to do it? Cheers,

Linux x86_64 + JIT bracktraces

Matthew Flatt — 2008-11-27T19:54:03

For Linux x86_64 users: the current SVN version now supports exception backtraces (the part after "=== context ===" below) even when the JIT is enabled. Welcome to MzScheme v4.1.3.3 [3m], Copyright (c) 2004-2008 PLT Scheme Inc. > (define (f x) ((x))) > (f 1) procedure application: expected procedure, given: 1 (no arguments) === context === stdin::1: f /Users/mflatt/proj/plt/collects/scheme/private/misc.ss:74:7 Let us know if it doesn't seem to work right, especially as compared to a 32-bit x86 build. Thanks to the libunwind team (David Mosberger-Tang et al.) for the DWARF-2 support. Matthew _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Happy Thanksgiving, PLT

Geoffrey S. Knauth — 2008-11-27T05:02:58

On this Thanksgiving Day, I am especially thankful for PLT. _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

HtDP: 'Function' or 'Program' or 'Method'?

Grant Rettke — 2008-11-26T21:50:10

When you guys teach HtDP do you call functions: functions, programs, or methods? Why one over another? _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Web Server Templates - absolute paths?

Eddie Sullivan — 2008-11-26T21:29:59

Thanks Jay McCarthy and all who worked on the templating system for the PLT Web Server. I've started playing with it, and it seems very cool. I do have one question: From my experiments, it seems include-template requires a relative file path, and does not except an absolute path. For example, if I try: (include-template "c:/path/template.html") I see the following error: include-at/relative-to/reader: bad relative pathname string in: "c:/path/template.html" Is there any way to make this work with an absolute path? Thanks. -Eddie Sullivan _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

PLT Scheme v4.1.2 (mac)

Tommy Nordgren — 2008-11-26T20:57:23

have language set to R5RS Where is append! ? ---------------------------------- Skinheads are so tired of immigration, that they are going to move to a country that don't accept immigrants! Tommy Nordgren tommy.nordgren-hLCdTlpAlG6zQB+pC5nmwQ< at >public.gmane.org _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-scheme

Fw: Mutable and immutable pairs in PLT Scheme

Jos Koot — 2008-11-26T20:15:12

I should add that I have severeal PLT implementations of SRFI-41. My latest one does not use mutable pairs, but it deviates from the standard implementation by streams not being a distinct data type. I have asked private advice from someone I trust, on whether not this would be an a good idea.. I await his answer before deciding whether or not presenting it to this list. I also have an implementation that fully conforms to the standard SRFI 41 document, but it requires a generalizarion of PLT's implementation of SRFI 45 (which would include `define-promise-type' and which I have prepared too, of course, and shall distribute if the PLT community is interested) I am not reluctant too distribute my code, but on the other hand I don't wish to spoil this mailing list with yet another idea of how to implement SRFI 45 or SRFI 41. Particularly SRFI 45 is a delicate piece of code, which should not be replaced by code that cannot fully be trusted. Oh yes, I trust my code, but would you? Jos ----- Origin

Mutable and immutable pairs in PLT Scheme

Thomas Chust — 2008-11-25T23:09:19

Hello, the discussion about R6RS support in PLT Scheme brought the topic of immutable pairs in PLT's default Scheme dialect to my attention again. Basically, I think having immutable pairs as the default is a good thing, but I start wondering why mutable and immutable pairs are completely disjunct types. Other datatypes, like strings, vectors and hash tables, that also exist in mutable and immutable variants in PLT Scheme, are not disjunct, but the pairs, maybe the most prominent datatype(s) of Scheme, behave differently. Is there any clever rationale behind this? I would actually have expected that the following conditions all hold (pair? (mcons 1 2)) (pair? (cons 1 2)) (not (immutable? (mcons 1 2))) (immutable? (cons 1 2)) However, mutable pairs are not pairs, as far as pair?, car and cdr are concerned and immutable pairs are not immutable, as far as immutable? is concerned. This seems totally counterintuitive to me! So unless there is a deeper reason for the disjunctness of the mutable and