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
Your best bet is to define a new language that overrides define after taking
over the body of the module. This may even be an example in the docs.
On May 18, 2015, at 9:39 AM, Mianlai Zhou wrote:
> Hi Matthias,
>
> Thanks for answer. However, this is not what I wanted:
>
#lang racket
(define/match (f n)
[(#t) 2]
[(#f) 3]
[(_) 0])
(list (f #t) (f #f) (f "where's my homework"))
On May 18, 2015, at 9:04 AM, Mianlai Zhou wrote:
> Hi Racketeers,
>
> I am a new user of Racket.
>
> I would want to be able to write the following segment of code:
>
> (defin
SICP isn' the bible, especially not on programming language knowledge. I'd
recommend checking out relevant literature instead.
On May 18, 2015, at 8:24 AM, Michael Tiedtke
wrote:
> Structure and Interpretation of Computer Programs (sicp2) about sameness:
>
> https://mitpress.mit.edu/
Constant propagation is not a property of a language but its implementation.
Few implementations document which transformations they currently implement.
-- Matthias
On May 18, 2015, at 7:11 AM, Jos Koot wrote:
> Very nice constant propagation in Racket.
> For example the Racket co
Correct. The question is meaningless. Thanks for the correction. -- Matthias
On May 13, 2015, at 11:44 AM, Li Junsong wrote:
> Hello,
>
> The `show' function above exercise 50 in HTDP2e draft (or exercise 52 in
> HTDP2e) is:
>
> (define (show x)
&g
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
What I'd much prefer at the moment over speculative solutions are reports of
actual performance bottlenecks. -- Matthias
On May 1, 2015, at 1:09 AM, michael.ballantyne wrote:
> I've started using Typed Racket several times recently only to flip the
> switch to #lang typed
Yes, at least one. See Racket manifesto. Any takers? Start with Shriram's
dissertation perhaps we need to go back there.
On Apr 26, 2015, at 4:43 PM, Neil Toronto wrote:
> On 04/26/2015 02:39 PM, Matthias Felleisen wrote:
>>
>> Once again, this is an instance where
On Apr 26, 2015, at 3:13 PM, Alexander D. Knauth wrote:
>
> On Apr 26, 2015, at 2:39 PM, Matthias Felleisen wrote:
>
>>
>> On Apr 26, 2015, at 9:18 AM, Alexander D. Knauth wrote:
>>
>>> I wanted to see if it could work for tests within (module+ test …),
ALex, Mira might be best served if you submitted all these things as issues via
github. -- Matthias
On Apr 26, 2015, at 1:04 PM, Alexander D. Knauth wrote:
> Also DrRacket doesn’t seem to want to quit. I click on the quit option in
> the menu, it asks me if I really want to quit, I
well for BSL, which is for
students who never programmed before.
Once again, this is an instance where you'd really like to abstract the library
over the language into which its exports are imported. This is a constant
struggle for me, and I'd like to solve it.
-- Matthias
--
Mira, you exist. I just submitted a bug report after installing the package and
playing with it. -- Also once you get the tool to work on HEAD, please enter it
into the catalog so it is easier to install. Thanks, this is really neat and
great to have -- Matthias
On Apr 25, 2015, at 9:43 PM
NICE!
On Apr 25, 2015, at 8:10 PM, Mira Leung wrote:
> Racketeer is a plugin for DrRacket that integrates continuous testing with
> Racket development. This is aimed primarily at the context of usage within
> university-level programming courses, and has been tested on computer science
> f
(n + n + n + t))
(n number))
(redex-match? jk t 1)
(redex-match? jk t (+ 1 1))
(redex-match? jk t (+ 1 1 1))
with the tools you have in Redex? -- Matthias
On Apr 24, 2015, at 5:30 PM, Jos Koot wrote:
> I have trouble translating the following into a define-language form:
>
>
No need for that. You can write your own renderer :-)
On Apr 22, 2015, at 1:02 AM, Gour wrote:
>
> Matthias Felleisen writes:
>
>> We'd love to have an additional renderer for Scribble.
>
> Good.
>
> Btw, is there something like Scribble-2 pl
We'd love to have an additional renderer for Scribble.
On Apr 21, 2015, at 7:05 AM, Neil Van Dyke wrote:
> Gour wrote on 04/21/2015 06:50 AM:
>>
>>> Another way to get to lots of different formats from Scribble would be
>>> to make Scribble generate more-plain HTML5 (i.e., less tag-heavy t
#lang typed/racket
(define-type NDigit (U 0 1 2 3 4 5 6 7 8 9))
(define-type SDigit (U 'zero 'one 'two 'three 'four 'five 'six 'seven 'eight
'nine))
(: to-string (-> NDigit SDigit))
(define (to-string i)
(case i
[(0) (displayln i) 'zero]
[(1) (displayln i) 'zero]
[(2) (displayln i
with
integration tests, import the former into the latter.)
-- Matthias
On Apr 16, 2015, at 11:17 AM, Konrad Hinsen wrote:
> Hi everyone,
>
> I want to put some order into my tests, but after looking at various
> published Racket packages, I am not sure if there any ac
iscuss off-topic ideas to some extent. You will get good and honest
answers.
-- Matthias
On Apr 7, 2015, at 3:31 AM, Giuseppe Luca Scrofani wrote:
> When, some day I will be, maybe, capable of really understand all of what you
> told me, I will dismiss my questions like this by mys
Take a look at the PLAI language and define-type. I recommend you elaborate
your syntax into PLAI constructs.
On Apr 13, 2015, at 12:40 PM, Nils Van Geele wrote:
> On Monday, April 13, 2015 at 6:26:38 PM UTC+2, Alexis King wrote:
>> What exactly is the difference here between your define-o
e with your analysis otherwise.)
-- Matthias
--
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 opti
In #lang languages syntax coloring happens on-line and is almost always close
to correct.
If you see a red dot in the bottom right of drracket, mouse over it, click to
enable syntax checking.
On Apr 9, 2015, at 2:59 AM, Jack Firth wrote:
> The DrRacket Check Syntax button colors syntax in
Jesse is a product of our NU lab. After a tour of Harvard (2x), he's back here
so he sees good syntax extensions at work every day. -- Matthias
On Apr 8, 2015, at 9:54 AM, "Geoffrey S. Knauth" wrote:
> See:
> http://www.quora.com/What-are-the-main-weaknesses-of-Has
You almost never have to worry about the efficiency of (second x) (cadr x) and
(car (cdr x)). There are always bigger fish to fry than that.
On Apr 6, 2015, at 3:37 AM, Lux wrote:
> It is more efficient (second myList) or (car (cdr myList)) if it is any
> difference at all?
> What are the p
bundle-string (explode "mumble") 2) (bundle-string (explode
> "mumble") 2))
I would be very surprised if (f x) were not equal (f x) for all functions f and
arguments x.
Please re-consider your example (formulated as test). This is where you went
wrong,
including setting up
you state and refute/validate such claims. But
as I say, this is a conjecture.
-- Matthias
On Mar 31, 2015, at 12:23 PM, Jonathan Schuster wrote:
> Forgot to reply to the list, so I'm forwarding here.
>
> -- Forwarded message --
> From: Paul van der Walt
> Da
You need to provide a running program, including inputs.
(You may also wish to read the style guide for Racket.)
On Mar 26, 2015, at 10:39 AM, chia kang ren wrote:
> http://pasterack.org/pastes/75790
> http://pasterack.org/pastes/11360
> http://pasterack.org/pastes/10455
--
You received th
Thanks. Fixed -- Matthias
On Mar 30, 2015, at 8:32 AM, Daniel Bastos wrote:
> Matthias, at least in this new address the PDF is a broken link. It currently
> points to
>
> http://www.ccs.neu.edu/home/matthias/manifesto/manifesto.pdf
>
> which yields a "file
Now that the scribble is mostly cleaned up, I have moved the manifesto to a
less temporary place:
http://www.ccs.neu.edu/home/matthias/manifesto/
-- Matthias
--
You received this message because you are subscribed to the Google Groups
"Racket Users" group.
To unsubscribe from
On Mar 27, 2015, at 4:11 AM, Konrad Hinsen wrote:
> Matthias Felleisen writes:
>
>>>> A web site is an ad.
>>>
>>> As is a research paper. It's the audience that differs.
>>
>> I am sorry but you embrace modern CS departments too much,
&g
[I am sorry for replying again on this sub-thread,
but your first statement makes me very sad and the
second one points out a serious flaw in our web prose.]
On Mar 26, 2015, at 11:02 AM, Konrad Hinsen wrote:
>> A web site is an ad.
>
> As is a research paper. It's the audience that differs
Thanks for sending this, again. I was writing a response very
much along these lines when your post came in.
1. No, we cannot and will not replace all tools. Quite the opposite,
I foresee a future in which we will produce many more tools. [Your
effort will make me think twice before I write a
Could you point to the complete code base? Thanks -- Matthias
On Mar 26, 2015, at 9:38 AM, chia kang ren wrote:
> Here is a clearer photo. In the original (and working) graphical editor you
> can select the entities to highlight them in red. The entities are weirdly
> cut off. The
nting of
a
big picture for people who explore the intellectual landscape of programming
languages
(as a whole and in principle) (especially w/o every programming much beyond
latex).
So please keep context in mind when you read our prose.
-- Matthias
--
You received this message because y
But yes, section 3 is the hard part and work on 4 and 5 is
"substitution" as Daniel Kahneman would say.
-- Matthias
--
You received this message because you are subscribed to the Google Groups
"Racket Users" group.
To unsubscribe from this group and stop receiving emai
Thank you Greg. I couldn't have said it any better (probably worse).
This is exactly the point -- Matthias
On Mar 25, 2015, at 12:07 PM, Greg Hendershott
wrote:
> My personal/casual take on this:
>
> There are language systems where you to need to run some
> make-a
On Mar 24, 2015, at 11:15 PM, Matthias Felleisen wrote:
> On Mar 24, 2015, at 10:34 PM, Neil Van Dyke wrote:
>
>> Shortly after I declare that Racket is not a cult, Racket goes and issues a
>> manifesto.
>>
>> Neil V.
Neil, I wrote this paper _because_ acade
We have just submitted the Racket manifesto for publication.
If you'd like to take a look at what has been on our mind,
here is scribbled version:
http://www.ccs.neu.edu/home/matthias/Tmp/manifesto/
The PDF is linked in. -- Matthias
Typos/scribbelos: to matth...@ccs.ne
On Mar 18, 2015, at 5:20 PM, Benjamin Greenman wrote:
> Switching to cons was an easy fix.
Not a fix. You get different errors at different times. Don't think "it works";
think "does it work for errors, too?"
Racket Users list:
http://lists.racket-lang.org/users
Are you sure? I had a drracket open in ISL and here is what I got:
> Welcome to DrRacket, version 6.1.1.8--2015-03-11(-/f) [3m].
> Language: Intermediate Student with lambda.
> > (require racket/runtime-path)
> > (define-runtime-path y "hello world")
> >
-
they should use their time to
read up on things that they know nothing about (lack of types in Racket)
instead of speculating about these things. Argh. -- Matthias
On Mar 18, 2015, at 8:53 AM, Sean Kemplay wrote:
> For those that are interested-
>
> https://news.ycombin
http://en.wikipedia.org/wiki/Zipper_(data_structure)
On Mar 17, 2015, at 1:14 PM, Alexis King wrote:
> That’s probably a good idea. I’m not quite sure what you’re referring to by
> “zippers”, though—could you elaborate?
>
>> On Mar 17, 2015, at 06:44, Matthias F
This is indeed exemplary. One thing I'd like to request in the README file is a
description of the "game's" idea. As for inefficiencies, consider using zippers
to lower the syntactic overhead; it may also help with allocation. -- Matthias
On Mar 17, 2015, at 12:17 A
ble to read Typed Racket’s error
> messages would probably be able to handle these ones. I’m not discounting
> your point—you’re right that this is probably less accessible for
> students—but I guess using it would be out of their grasp, anyway, at least
> for now.
>
>> On Mar 1
ld package did not.] --
Matthias
On Mar 14, 2015, at 8:39 PM, Alexis King wrote:
> I’ve had the 2htdp-typed package available for a little while now, which is a
> Typed Racket wrapper for the HtDP/2e teachpacks. It was missing big-bang,
> since it is implemented as a macro, b
On Mar 5, 2015, at 5:16 PM, Rufus wrote:
> Alex
>
>> [racket processes variable definitions first, then functions]
>
> Got it.
That's not true. When you evaluate a definitions area,
you evaluate a module body and that process proceeds
top to bottom for Racket definitions and expressions.
On Mar 4, 2015, at 1:18 PM, Rufus wrote:
> To All
>
> Using BSL-Lists:
>
> Matt't basic test works.
>
> (define rufus 0)
>
> Run, then type and execute "rufus" in the I-pane which displays 0
>
>
>
> If I then add Alexander's example define so the def file appears as follows:
> -
>
All of this should work out of the box, w/o any problem.
1. Please report on the following experiment. In the Definitions pane, type
(define rufus 0)
2. Click Run
3. In the Interactions pane, type
> rufus
4. Please report the response of DrRacket.
Racket Users lis
Use BSL with List Abbreviation.
On Mar 3, 2015, at 3:50 PM, Rufus wrote:
> Alexander
>
> Well, in fact, I thought it worked for me, too. And then it stopped
> working; DrR threw an "application: not a procedure;" error saying it
> was given a null list instead of an application. Removing th
comfirm and play w/the examples and exercises in TLS, first
> chapter. If it proves useful I'll add more definitions or else just let
> it quiesce.
>
> Matthias, All:
> So far I don't find any advantage to using "BSL w/List Abbrv". Since the
> quote characte
If the students are quick with it, move on to the first two parts of
HtDP/2e. See http://www.ccs.neu.edu/home/matthias/HtDP2e/index.html
3. If that's challenging, work thru it slowly. Supplement with games you can
make up that match that level of design.
4. If that's boring, move
Thanks. This is really neat. When (if really) I ever find time, I would love to
help with putting more of Realm out there like this. -- Matthias
On Mar 2, 2015, at 10:10 PM, Floyd Arguello wrote:
> trycode.io has been updated with the Guess My Number game from Realm of
> Racket.
The Little Lisper/Schemer uses ' (quote) for lists and that is not available in
plain BSL. You need BSL-with-list-abbreviations to follow along TLS/TLL.
On Mar 2, 2015, at 9:21 PM, Rufus wrote:
> Matthias
>
>> best advice
>
> Yes. Said as much to Jordan but my email
the -> Language ->
Choose Languages menu.
-- Matthias
On Mar 1, 2015, at 7:54 PM, Jordan Johnson wrote:
> On Mar 1, 2015, at 5:37 PM, Rufus wrote:
>> And also
>> a function to save this state (variables in the global environment) in a
>> fashion that could be q
ccasion it would be neat to say "stop here and
let me explore/modify the environment and the store." Most of the
time though you get away with printf because the language is safe
I just don't consider it high priority until someone shows me a
really good use case.
-- Matthias
The server doesn't need a GUI. It shows state windows and debugging windows
only when you specify appropriate clauses in its description. But, it pulls in
a shared library from 'world' that relies on racket/gui. So the answer is
'currently not possible but doable in princ
On Feb 27, 2015, at 8:37 AM, Konrad Hinsen wrote:
> - A teaching and research language for numerical problems, with
> first-class syntactical support for rationals, floats, bigfloats,
> and (dreaming...) exact reals.
I am sure Neil is working on this. --
Some well-known hackers tell you to learn "Lisp" to become a better programmer.
The idea of "Lisp" comes with several different connotations, only one of them
is "functional programming." Otherwise, as Neil says -- Matthias
On Feb 26, 2015, at 7:35 PM, Sergio
This is dang cool. How much of Realm can you get into this format? -- Matthias
On Feb 25, 2015, at 4:11 PM, Floyd Arguello wrote:
> I found that my daughters had a lot of questions when they went through the
> tutorial at http://try-racket.org/ - what’s a function? What’s a b
Don't make me want to go back to programming Racket in Emacs :-)
But thanks for mapping Emacs back into the fold. -- Matthias
On Feb 24, 2015, at 5:02 PM, Greg Hendershott wrote:
> Just a heads-up on some progress with racket-mode over the last couple
> months:
>
> - Suppo
I am not offended. I am saddened.
On Feb 24, 2015, at 1:25 PM, Andrew Kent wrote:
> I just grabbed two separate witnesses showing the result of the relevant
> floating point math - I apologize for any offense.
>
> On Tue Feb 24 2015 at 1:15:01 PM Matthias Felleisen
> wro
That's the saddest argument in support of anything Racket I have ever seen
(even with the smiley).
On Feb 24, 2015, at 1:05 PM, Andrew Kent wrote:
> Racket:
> (+ .1 .1 .1 .1 .1 .1 .1 .1)
> 0.7999
>
> Python:
> >>> .1 + .1 + .1 + .1 + .1 + .1 + .1 + .1
>
> 0.7999
>
Why do you want that? It's confusing to write x : x. I'd prefer x : X anyways.
On Feb 22, 2015, at 2:43 PM, Alexander D. Knauth wrote:
> Using #:omit-define-syntaxes doesn’t work because then when other modules
> import it it forgets about the type:
>
> def.rkt:
> #lang typed/racket
> (provi
For the first half of the question, see
http://www.ccs.neu.edu/home/matthias/HtDP2e/part_4.html#%28part._sub~3areading-xml%29
from the book for absolute novices. It explains how to design a simple stock
ticker by reading (X)HTML off the web.
The book emphasizes systematic design. You can
Here are some realistic, non-contrived examples where I use macros like
thread-through [called build-scene] a lot:
;; Image Number Number -> Image
;; (x0,y0) is where we want to add a branch
(define (fork s0 x0 y0)
(define xB (x-B x0))
(define yB (y-B y0))
(define xC (x-C x0))
(define
abuse `let` to have your
>> `define`s:
>> (let ()
>> (define x 3)
>> (define y 4)
>> (list x y))
>>
>> It's even more vicious if you use `let*` instead of `let`, but quite less if
>> you use `begin` instead ;)
>>
>>
>>
&
In some places, you are allowed only one expression, and for that situation,
you need let*.
On Feb 19, 2015, at 12:40 PM, Don Green wrote:
> What is/are the reason(s) for choosing the 'let*' construct over the 'define'
> construct?
>
> (define (print-two f)
> (let* ([_ (print (first f)
compromise between those two concepts and have an obligation to show learners
that there is an issue. I consider *SL in a sweet spot, despite the warts that
occasionally show up.
-- Matthias
On Feb 18, 2015, at 8:28 AM, Nadeem Abdul Hamid wrote:
> And you can use
>
> > (number-&
recommend developing small units in one DrRacket buffer. It's the
easiest way to get used to their syntax.
-- Matthias
On Feb 4, 2015, at 9:14 PM, Justin Zamora wrote:
> There seems to be a problem exporting struct constructors when using #lang
> racket/signature. This works:
First, you figure out the sections on designing programs and functions.
Second, you move on to the editor sections:
http://www.ccs.neu.edu/home/matthias/HtDP2e/part_one.html#%28part._sec~3aedit1%29
http://www.ccs.neu.edu/home/matthias/HtDP2e/part_two.html#%28part._list-edit._sec~3alis%29
the math library and I am sure he will pipe in soon.
-- Matthias
Racket Users list:
http://lists.racket-lang.org/users
ed by Racket. Our
experience with that angle is great.
Of course, this is not the same as building apps with Racket (for Android). But
I agree that there is a chance and I encourage you to pursue this idea
-- Matthias
On Jan 29, 2015, at 3:34 AM, Byron Davies wrote:
> The XPRI
ent itself inside [pain-callback (lambda ... functions
> ) under definition of canvas, but it looks strange and clumsy.
> Sometimes I need just to run computations, but sometimes I need also to do
> visualization with animation.
>
> How could I achieve this?
>
> Best regards
define (my-draw)
(send (send canvas get-dc) draw-line 100 100 0 200))
-- Matthias
On Jan 27, 2015, at 12:09 PM, Alexandr M wrote:
> Hello,
>
> How can I draw the line (for example) in the canvas object defined as:
>
> (define frame (new frame% [label ""] [width 7
1. You should make your macro robust and deal with fewer than two elements in
your uses.
2. Here is the same idea w/ syntax-rules:
#lang racket
(define-syntax quote-even
(syntax-rules ()
[(_) '()]
[(_ zero) (list 'zero)]
[(_ zero one two ...) (list* 'zero one (quote-even two .
Try that:
@(toc-element #f "" (hyperlink "http://www.ccs.neu.edu/home/matthias/";
"Home"))
-- Matthias
On Jan 26, 2015, at 4:19 PM, David Van Horn wrote:
> On 1/26/15 4:14 PM, Stephen Chang wrote:
>>> Is there a way to make @link that appea
Just a few MF-labeled comments -- Matthias
; An Xexpr.v0 (short for X-expression) is
; (cons Symbol '())
(define sv0.0 (cons 'machine empty))
(define sv0.1 (cons 'another empty))
;These v0 I'm confident.
; An Xexpr.v1 is
; (cons Symbol [List-of Xexpr.v1])
(define
mes -- and here it breaks this rule, so
a comment is in order. -- Matthias
On Jan 22, 2015, at 11:37 AM, Daniel Bastos wrote:
> Near exercise 305, HtDP/2e says that "[in] ISL+ (... and in the currently
> popular scripting languages) such an informal signature with a definite
> me
ines above and below). Good start. Mostly: cut
junk, organize top down (most important to less important to least important
functions). -- Matthias
(require 2htdp/image)
(require 2htdp/universe)
;Exercise 197. Consider the following data representation for finite state
machines:
(define-struc
I prefer leaving it alone but documenting the limitation -- Matthias
On Jan 23, 2015, at 9:30 PM, Robby Findler wrote:
> Maybe the right thing to do is leave the arbitrary limit in there, but
> make it based on the area, not based independently on the width and
> height. Then you
t would be superfluous to repeat every TR function in the documentation,
> it still could be valuable to document some of the major departures from
> Racket. I mean, I would read that, for sure ;)
Actually it would not be superfluous. We just don't have the ma
If you are new to Racket, you may wish to read How to Design Program 2e's
Prologue:
http://www.ccs.neu.edu/home/matthias/HtDP2e/
On Jan 23, 2015, at 11:48 AM, Alexandr M wrote:
> Hello dear community members,
>
> I am trying to build a GUI with a very simple animation - jus
an believe this, the documentation for that function even
> *gives example code* for computing cumulative sums!
>
> Stupid git.
>
> Neil ⊥
>
> On 01/22/2015 07:35 PM, Matthias Felleisen wrote:
>>
>> NOTE TO EVERYONE: The OP asked for "without usage of any
it cannot dispatch
in response to Racket. -- Matthias
On Jan 22, 2015, at 11:39 AM, Luke Whittlesey wrote:
> Hello,
>
> I've been learning TR, but I seem to have gotten myself into a corner that I
> haven't been able to find a workaround for. I'm looking for some
NOTE TO EVERYONE: The OP asked for "without usage of any libraries".
I am sure that sooner or later we will find a library so that we
can say (require lib/cumulative) cumulative-sum.
On Jan 22, 2015, at 7:16 PM, William James wrote:
> Here's a way using map-accum in Gauche.
>
> (use gauche.
l + 0)
>(build-list (length xs)
>(compose (curry take xs)
> add1))))
>
> On Thu, Jan 22, 2015 at 6:34 AM, Matthias Felleisen
> wrote:
>
> #lang racket
>
> ;; [Listof Number] -> [L
I think these non-standard situations could be dealt with by an optional
keyword argument to @item:
@item[#:label "3a"]{...}
-- Matthias
On Jan 22, 2015, at 7:49 AM, Matthew Flatt wrote:
> Oh, good point. I had checked Latex and HTML, but I didn't think to
>
#lang racket
;; [Listof Number] -> [Listof Number]
;; given (a b c ...) produce (a (+ a b) (+ a b c) ...)
(define (cumulative-sum l #;"final private:" [so-far 0])
(cond
[(empty? l) '()]
[else (define next (+ so-far (first l)))
(cons next (cumulative-sum (rest l) next))]))
(
for your support, and congratulations to the
> Scribble designers: its really a great environment to work with.
This is how I run a draft or a release version of HtDP/2e:
#! /bin/sh
#|
exec /Users/matthias/plt/racket/bin/racket -tm "$0&q
tp://www.ccs.neu.edu/racket/pubs/#esop14-gjthf (which is a conference
publication) and follow the link to supplemental information. Marketplace and
Minimart are of course available as packages.
Warning: both are prototypes and will evolve (probably into another language).
-- Matthias
I have replaced the second "occurrence" of cases with "complete conditional."
Perhaps this will help a future reader. Thanks -- Matthias
On Jan 19, 2015, at 7:55 AM, Daniel Bastos wrote:
> Exercise 48. If you copy and paste the above function definition into the
thing as moving from the typed to the untyped world
(and vice versa).
Perhaps an example like Jordan's could be included in the docs.
-- Matthias
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t-field an-instance-of-add-item)
...
;; And further down you add a method add:
(define/public (callback event . x)
(send an-instance-of-add-item add-item ... stuff ...))
))
-- Matthias
On Jan 17, 2015, at 8:15 AM, mazert wrote:
> Hello,
>
> I have two files :
>
On Jan 15, 2015, at 10:56 AM, Daniel Bastos wrote:
> (*) Curiosity
>
> 1. I wonder what BS stands for in this definition.
>
> ; A BS is one of:
> ; — "hello",
> ; — "world", or
> ; — pi.
>
> Is it just a synonym for nonsense?
Nothing in particular but I should change it because of its bad c
[cc user@ again]
There is no bug in syntax-rule/s.
Macros do not evaluate anything. They rewrite code. Code refers to identifiers.
This relation must remain apparent.
That's it. -- Matthias
On Jan 14, 2015, at 9:57 PM, Thomas Lynch wrote:
> As for the demonstrative
On Jan 14, 2015, at 8:14 PM, Thomas Lynch wrote:
> Matthias thank you for fielding my question, though two things are not clear.
> I hope you or someone might clarify.
>
> Firstly, is there a reason to prefer the macro you present over the first
> one given in the or
You want something like this:
(define-syntax (with-tables stx)
(syntax-case stx ()
[(with-tables stem body ...)
(let ([table-author (datum->syntax stx 'table-author)]
;; ... ditto for other identifiers for which you wish to break
lexical scope
)
#`(let
x27;t appear: to the left of a )
> ; readline-input:4:8: read: unexpected `)'
> -> (+ 10 x' )
Same here.
;; ---
In principle, ' would be good to use as part of a name but I prefer to use it
for quoted S-expressions if that's the choice I have. Then again, I
cycle instead
(3) resume our regular release rhythm this spring.
Thanks for your patience.
Matthew, Robby, Sam, Ryan, Jay, and Matthias
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