t;a" ...))
and be done.
> You could also design a weird function that does completely different things
> depending on what the arguments are, like this:
For fun, you can write any kind of function you like.
As long as you design these functions to match the structure of the dat
test the whole
code base). So if you're thinking of package contributors,
keep this in mind -- Matthias
On Aug 23, 2013, at 2:09 AM, Chad Albers wrote:
> Thanks everyone for their feedback. Keep it coming! I didn't know
> about the ability to include tests next to the
a bit out of sync on occasion.
The next step is Realm of Racket. And it's well within your reach, including a
teaser chapter.
-- Matthias
Racket Users list:
http://lists.racket-lang.org/users
Here is one more alternative:
#lang racket
;; you can move the body of this module into a '#lang racket' file called
fuzzy-set-library.rkt
(module fuzzy-set-library racket
;; rename-out is an elegant version of the let()/define-values trick in Realm
of Racket
(provide (rename-out (fuzz
rst.)
Because:
We picked the full language that we thought offers a decent goal (Racket) and
developed teaching languages that gradually approximate the language but
provide good feedback.
-- Matthias
On Aug 24, 2013, at 4:38 AM, Ben Duan wrote:
> Dear All,
>
> Here’s a beginner
I don't see how either Scratch or Bootstrap can deliver the promised iOS app.
But why don't you try Scratch first and report back to us, then try
bootstrap-world.org -- Matthias
On Aug 24, 2013, at 1:07 PM, Grant Rettke wrote:
> Hi,
>
> My nephew seems pretty intere
With Bootstrap your nephew can at least share his games with friends and family
on the web right away. Not a native app.
On Aug 24, 2013, at 7:26 PM, Grant Rettke wrote:
> On Sun, Aug 25, 2013 at 3:51 AM, Matthias Felleisen
> wrote:
>> I don't see how either Scratch
Does this help:
> #lang racket
>
> (module+ test
> (require rackunit))
>
> ;; ---
>
> (module+ test
> (define-test-suite for-f
> (check-equal? (f 10) 10)
> (check-equal? (f 11) 12)))
>
> (define (f x)
> x)
>
>
> (module+ test
> (require rackunit/text-ui)
> (run-tests fo
Have you considered mining the style guide for such rules? -- Matthias
On Aug 26, 2013, at 2:03 PM, Jordan Johnson wrote:
> Hi all,
>
> This fall I'm planning to be doing some further work towards a framework for
> writing briefer checker scripts for Eli's ha
#x27;c .2)
> (fuzzy-element 'd .3)))
>
> in the way you defined fuzzy-set above, how do you create the function
> fuzzy-set? and how do you create fuzzy-first and fuzzy-rest ?
>
> Thanks,
> Rian
>
> On Aug 23, 2013, at 8:02 PM, Matthias Felleisen wrote:
>
ore static approach to
structs than other scripting languages, from which you get a bit more safety
and a bit more hassle.
-- Matthias
On Aug 27, 2013, at 12:37 AM, Danny Gratzer wrote:
> Hello,
>
> I'm writing some code to manipulate a few structs and in doing so have
ed to know the struct type. I bet that this will work more
easily than structs plus other macrology.
-- Matthias
On Aug 27, 2013, at 11:33 AM, Danny Gratzer wrote:
> It's part of a DSL I'm writing, the idea being a user gives an accessor to
> some struct, a function to t
You should not have to install as admin. Are you on 10.8 by any chance?
On Aug 27, 2013, at 4:30 PM, Tristian Paul Lpez Azuara
wrote:
> Hello,
>
> Nice to meet every one, I'm trying to use the racket language on a 32-bit
> Mac OS, the problem is that in order
> to install it, I need to
with the richest
system of syntax extensions.
-- Matthias
On Aug 27, 2013, at 7:48 PM, George Rudolph wrote:
> I understand the idea of refactoring code to make it testable.
> I very much appreciate the clarification on usage. Thank you.
> But...
> As I see it, th
of
users -- commercial, open source, extreme hobby, and the full range of
educational efforts -- and we are hoping that people speak up when things go
wrong.
>From the very beginning of this project in 1994, we made feedback from users
>our highest priority and we will continue to do so.
-
by Plotkin's 1973 paper on
"call-by-name, call-by-value, and the lc" in TCS. There are stone-aged authors
who can't resist using this terminology but we should be enlightened enough to
know that this is a bogus term w/o well-defined meaning :-)
-- Matthias (heart-felt as you
On Aug 28, 2013, at 12:33 PM, Grant Rettke wrote:
> On Wed, Aug 28, 2013 at 11:04 PM, Matthias Felleisen
> wrote:
>> For the record, there is no such thing as 'applicative order.' There is
>> call-by-value and there is a humongous misunderstanding
>> ca
On Aug 28, 2013, at 12:41 PM, Alexander McLin wrote:
> In fact I learned that in SCIP, so I need to check when the edition I have
> was published to see how old it really is.
See other email. Bottom line is that Gerry and Hal are not PL researchers --
never have been -- and I doubt that they
No problem.
While we are on names. We use
-- "Matt" for Matthew Might, a Utah researcher who also uses Racket;
-- "Matthew" for Matthew Flatt, the CEO of PLT Design, Inc, creator of Racket,
and ruler of the kingdom
-- "Matthias" for me, which yes, is a for
We don't test contracts. In general contracts are relatively simple functions,
but yes, we have written several papers on bugs in contracts and how this
complicates a contract monitoring system.
If you are asking how to test functions that have contracts, I import that
module itself into a su
hen it is given 2 it returns
the right one. (I am too uninformed to say whether you can literally return
distinct types instead of distinct variants but I believe this to be the case.)
In Typed Racket, you return a union type and you can then use subtyping to get
the corr
s error
message [format] and that you aren't the last one. But changing it isn't easy
and adding information isn't easy. The problem is that we wish to keep the
messages uniform across all functions but not all functions can benefit from
the actual contract system.
-- Matthias
Racket Users list:
http://lists.racket-lang.org/users
You're right on. Let's see what we can do -- Matthias
On Sep 2, 2013, at 4:57 PM, Daniel Prager wrote:
> Hi Matthias
>
> Thanks for the explanation - it helps. I played with the kind of
> post-condition "broken contract" example that you gave, and find i
e careless.
See binary-search but impose sorted? as a predicate on the vector
that flows into the function.
Good luck -- Matthias
On Sep 3, 2013, at 2:37 AM, Daniel Prager wrote:
> I'm giving this talk
>
>
> http://www.slideshare.net/DanielPrager/introduction-to-c
On Sep 3, 2013, at 5:51 PM, Daniel Prager wrote:
> Hi Matthias
>
> Thank-you for your sage advice:
>
> On Tue, Sep 3, 2013 at 11:54 PM, Matthias Felleisen
> wrote:
>
> 1. Always use contracts that cannot be expressed as types
> in an obvious type system.
>
On Sep 7, 2013, at 9:43 AM, Konrad Hinsen wrote:
> That sounds reasonable, but in the scenario we are discussing
> (accessing data structures implemented in Typed Racket from
> plain Racket), the data structure never passes in that direction,
> except if it's constructed from a plain Racket data
I wonder whether you really want lazy streams. -- Matthias
On Sep 9, 2013, at 10:19 AM, Lawrence Woodman wrote:
> On 09/09/13 07:19, Stephen Chang wrote:
>> Konrad's exactly right. Your filtered-nums blows up because you named
>> the stream and then traversed the entire t
Lift the module definition to top and require in the expression position?
On Sep 13, 2013, at 12:08 PM, Eric Dobson wrote:
> I want to write a macro which generates submodules and then possibly
> requires them. This is so that can easily use another language (TR)
> for the expression.
>
> If
figure this out. Right now I
urge you to point your students to this mailing list so that they can get help
directly. As you probably know, people here are eager to help and it doesn't
take a core developer to respond (as Robby already pointed out).
-- Matthias
On Sep 14, 2013, at 10:
Why is RacketCon not advertised on racket-lang.org?
On Sep 18, 2013, at 4:43 PM, Asumu Takikawa wrote:
> On 2013-09-19 06:30:24 +1000, Daniel Prager wrote:
>> Will the prsentations, or at least the keynotes, be recorded and made
>> available?
>
> Yes, we will be recording the talks. We also
On Sep 20, 2013, at 1:05 PM, Alan Johnsey wrote:
> It looks like I’ve stumbled into another area where I’m lacking a basic
> understanding of what’s going on. I’m trying to use the built-in editor in
> the gui package, but I need to put some initial content into the editor
> window. When I pu
d on what is in the text% object.
>
> Robby
>
>
> On Fri, Sep 20, 2013 at 8:40 PM, Alan Johnsey wrote:
> Thanks. That will do for now, but it remains a mystery to me why my approach
> doesn’t work.
>
> -Alan
>
>
>
>
>
> From: Matthias Fell
#lang racket
(require (except-in 2htdp/image image?))
(require lang/htdp-advanced) ;; <-- this appears to override except-in, so
stick to this order
(require 2htdp/universe)
On Sep 21, 2013, at 5:50 AM, Manfred Lotz wrote:
> Hi there,
> How could I use template variables (... aso.) when usi
Is the following code really that much more complicated that define-macro? --
Matthias
#lang racket
(require (for-syntax syntax/parse))
(define-syntax (new-field stx)
(syntax-parse stx
[(_ f:id) #'(new-field f null)]
[(_ f:id default-value)
(define field-name (append-i
I wanted to show how to define auxiliary functions for syntax processing,
something you do wish to know when you come from Emacs/CL
On Sep 23, 2013, at 12:31 PM, Sam Tobin-Hochstadt wrote:
> On Mon, Sep 23, 2013 at 11:59 AM, Matthias Felleisen
> wrote:
>>
>> (define
What if we suggest some games to implement? He'd be alone but surrounded by
Racketeers who know.
On Sep 23, 2013, at 8:15 PM, Geoffrey S. Knauth wrote:
> I'm bringing my 16 year-old son to RacketCon on Sunday, since he loves
> Racket. It's also the weekend of my college 30th reunion. On th
On Sep 25, 2013, at 7:59 AM, Sam Tobin-Hochstadt wrote:
> I think the error message could be better
Yes. Please.
Racket Users list:
http://lists.racket-lang.org/users
what I can tell though it
may not eliminate the actual performance bottleneck.
That's about all I can say -- Matthias
On Oct 4, 2013, at 2:49 AM, Andrews, Kyle (KC) wrote:
> Near the end of Matthew Bassett’s talk at RacketCon someone mentioned that
> the Racket developers had int
No images in 2htdp and htdp differ and there's some funny exporting/importing
going on to get the predicates into the right place because they also work on
copied/pasted images.
On Oct 8, 2013, at 7:51 PM, Stephen Chang wrote:
> Ok, I didn't realize they were different functions. I thought
It would be wonderful if someone could update either Joe's or Greg's tutorials
on contributing at this level for the brave new world of packages. Or at least
put it on the list for the next hackathon and perhaps include it in the docs.
-- Matthias
Ra
0. Racket is not Scheme and this an example where the difference shows up.
1. Use the legacy language Pretty Big:
Welcome to DrRacket, version 5.90.0.9--2013-10-15(efaa5bd1/d) [3m].
Language: Pretty Big.
> (load "functions.scm")
>
2. Even then, some functions are simply not defined in "Schem
sider using Shriram's PLAI; it's the grandson
of EOPL and supported by some Racket devs.
-- Matthias
On Oct 20, 2013, at 1:43 PM, Kurt Krebsbach wrote:
> Hi,
>
> I’ve been using EOPL2 to teach Programming Languages for a dozen years now,
> and am having a great dea
n the most mathematical
manner and consult OC to see how to squeeze the most out of this style.
When I found that certain styles don't get optimized the way I expect
them to get optimized, I would ask the Racket devs whether they could
make improvements so that specific functions/programs work better.
-- Matthias
Racket Users list:
http://lists.racket-lang.org/users
WIth respect, I think this shows nothing :-)
On Oct 21, 2013, at 2:35 PM, Sam Tobin-Hochstadt wrote:
> On Mon, Oct 21, 2013 at 12:47 PM, Matthias Felleisen
> wrote:
>>
>> In general, it is a mistaken assumption however that even in a
>> 'managed'
ither -- Matthias
On Oct 22, 2013, at 8:14 AM, Robby Findler wrote:
> I did this explicitly because (I believe) it helps with parenthesis errors
> when beginning students make simple mistakes using the library. For more
> advanced programmers, it seems straightforward to defi
u will want to iterate over these things or
access fields via computation. -- Matthias
Racket Users list:
http://lists.racket-lang.org/users
;; equation3 : number -> boolean
;; to determine whether n is a solution for 2n^2 = 102
(define (equation3 n)
(=~ (* 2 n n) 102 .001))
-- Matthias
On Oct 22, 2013, at 8:40 AM, Bo Gus wrote:
> equation 2 is 2n^2 = 102 so I implement like this:
>
> ;; equation3 : number
Hi BoGus,
fwiw, this exercise is NOT in HTDP 2nd edition but HTDP 1st edition, 1-4th
printing.
Just in case you really want to work through HtDP 2e.
-- Matthias
On Oct 22, 2013, at 8:53 AM, Matthias Felleisen wrote:
>
> ;; equation3 : number -> boolean
> ;; to determi
On Oct 23, 2013, at 6:25 PM, Erik Pearson wrote:
> Excuse my poor experience with contracts, this is probably an easy one.
>
> I'm using a copy of net/url and have a strange problem. The copied library is
> working fine in general, but this problem cropped up today:
>
> struct:exn:fail:con
Or you defined
(struct url ...)
somewhere :-)
On Oct 23, 2013, at 6:31 PM, Jay McCarthy wrote:
> Here are two ideas.
>
> 1) You simply have an old use of the original net/url. When # is
> printed, it uses the symbolic name and you can't really figure out
> what the underlying code came f
:
http://www.ccs.neu.edu/racket/Performance/
[I know Sam knows all this because he's my student, and I simply
expressed my frustration that he'd write a message that is so totally
inconsistent with his knowledge.]
-- Matthias
On Oct 24, 2013, at 6:44 AM, Gustavo Massaccesi wrote:
(y)) (if (eq? yard d) (yard (meter->yard y)) x)]))
;; auxiliaries
(define (yard->meter v) (* .9 v))
(define (meter->yard v) (/ v .9))
-- Matthias
On Oct 26, 2013, at 7:20 AM, Laurent wrote:
> Ok, so I just hacked together a small lib for handling numbers with unit
> symbol
1. I would hope that some generics might help here.
2. I see a need for struct mixins here because meter isn't a refinement per se
but some 'attribute'. Then you could mixin several different units and I may
have both m and m-1.
Data representation not fully thought thru. -- M
see some experimentation here because people haven't
explored the space much and Racket could help explore a #lang metric/racket and
even #lang typed/metric/racket.
-- Matthias
On Oct 26, 2013, at 11:36 AM, Matthias Felleisen wrote:
>
> 1. I would hope that some generics mig
You may wish to read through HtDP/2e:
http://www.ccs.neu.edu/home/matthias/HtDP2e/index.html
strings: "silly"
symbols: 'silly
all lists are made from cons and empty,
list
quote '
quasiquote `
unquote ,
are abbreviations that expand to lists:
http://www.ccs.n
Once I had fixed the typo in your program, I was able to run this loop without
ado:
> (for ((i (in-range 9))) (collect-garbage) (collect-garbage) (time (main i)))
cpu time: 1 real time: 1 gc time: 0
cpu time: 5 real time: 6 gc time: 0
cpu time: 9 real time: 9 gc time: 0
cpu time: 77 real time:
Okay this suggests it's a Window's problem because I am running on a Mac
desktop with half the memory and I can go to 9 or 10.
I have cc'ed Ryan who created and maintains the DB support. Perhaps he can
narrow down the problem.
Thanks for the wishes -- Matthias
On Oct 29
Thanks, fixed and pushed. -- Matthias
On Nov 2, 2013, at 6:39 AM, Laurent wrote:
> From a question on StackOverflow [1], it seems that on this page:
> http://www.ccs.neu.edu/home/matthias/HtDP2e/part_4.html
> unsyntax `#,' appears 3 times, in places where it should probably no
site.
>
> Laurent
>
>
> On Sat, Nov 2, 2013 at 3:02 PM, Matthias Felleisen
> wrote:
>
> Thanks, fixed and pushed. -- Matthias
>
>
>
> On Nov 2, 2013, at 6:39 AM, Laurent wrote:
>
> > From a question on StackOverflow [1], it seems that on this pa
Please work your way thru HtDP/2e first. Realm assumes people have seen a full
course on programming (2e is almost complete) and have the maturity to work
through some typical first problems. When you're done Realm will be just fine
for you. -- Matthias
On Nov 3, 2013, at 6:19 AM,
I tend to define such constants in a file dubbed 'basics' and require it
everywhere. See
https://github.com/mfelleisen/Acquire
for example. There 'basics' contains the constants I need for most of the game
implementation and some simple functions too.
-- Matthias
s a monad for bridging the gap between the two styles.
(Not Racket language model per se but it's not clear what you're really
interested in.)
-- Matthias
On Nov 5, 2013, at 8:01 AM, Sam Tobin-Hochstadt wrote:
> In general, papers here: http://www.ccs.neu.edu/racket/pubs/ and also
&g
oldl + 0 l))
;; [List-of Number] -> Number
;; add numbers from right to left
(check-expect (sumrl '(1 2 3)) 6)
(define (sumrl l) (foldr + 0 l))
Then apply the two functions to JANUS. Enjoy -- Matthias
Racket Users list:
http://lists.racket-lang.org/users
Lovin' it. I am writing the draft of HtDP/2e in Scribble:
http://www.ccs.neu.edu/home/matthias/HtDP2e/index.html
and I have had several requests for the content menu to slide along in the left
margin.
I think it would be okay if searching remained at the top, and the content menu
Have you considered classes instead of structs? -- Matthias
On Nov 9, 2013, at 12:50 PM, David T. Pierson wrote:
> Hi all,
>
> Sometimes when defining struct types it is useful to have fields which
> are essentially "private" to the module (fields whose accessors/mutat
I think this is the program you want:
#lang racket
(module+ test
(require rackunit))
;; [List-of Real] -> [List-of Real]
(module+ test
(check-equal? (roulette-wheel-ratio '(1 2 3)) '(1/6 2/6 3/6)))
(define (roulette-wheel-ratio generation-fitness)
(define total-population-fitness (f
Lawrence, let me supplement Alex's answer. if you have programmed before, dive
right into Realm. If it is your first real adventure in programming, take the
time to work through HtDP. -- Matthias
On Nov 12, 2013, at 12:47 PM, Alexander McLin wrote:
> Racket is truely a great and
On Nov 12, 2013, at 11:55 PM, David T. Pierson wrote:
> Do you really need a file stream port and not just an input port?
Vlad, are you looking for pipes?
Racket Users list:
http://lists.racket-lang.org/users
for Realm. Is it written for kids? I
> have already spent some time in Racket and want to read some idiomatic Racket
> code. Is it a suitable book?
>
> Thanks,
> Ben
>
>
> On Wed, Nov 13, 2013 at 3:20 AM, Matthias Felleisen
> wrote:
>
> Lawrence, let me su
Do you want something like this :
#lang racket
(define-syntax-rule
(lambda/contract (x ...) c e0 e ...)
;; ==>
(let ()
(define/contract (f x ...) c e0 e ...)
f))
;; -
(define g (lambda/contract (x) (int
local is a teaching construct that ensures that the semantics of locally
defined functions is 100% in sync with 'globally' defined functions. An
experienced programmer may ignore local completely. -- Matthias
On Nov 13, 2013, at 3:52 PM, Manfred Lotz wrote:
>
> (defin
Kind of. If this is about Universe programming (so that students can send
messages back and forth), I have them write conversion functions:
(define-struct hh (cakes henries))
(define (hh->lists hh)
(list (cakes->lists (hh-cakes hh)) (henries->lists (hh-henries hh
-- Matthi
tions. I do not believe that they are actually
> serializable, but we could fairly easily make that change.
>
> On Sat, Nov 16, 2013 at 10:22 AM, Matthias Felleisen
> wrote:
>>
>> Kind of. If this is about Universe programming (so that students can send
>> messages
ve single files for solutions.
The former helps with the latter. The former is important for weaker
students. In my own courses, I switch partners between assignments
for which you may need to repair (not include) code from previous
assignments.
-- Matthias
On Nov 16, 2013, at 8:39 PM,
ck, they need to switch partners, they need to
explain code to each other and decide which code base to move forward
with.
-- Matthias
Racket Users list:
http://lists.racket-lang.org/users
e. I tried doing this using
> > >> "require", but I cannot figure out how to get "require" to load a file
> > >> that is written in Intermediate Student Language. Is there another
> > >> mechanism I should try? Is the thing I want to do even poss
In my experience, using plain require and later adding 'except-in' when a
service module decides to widen its interface is a much simpler approach than
pre-emptively using 'prefix-in' or 'only-in', especially if you need (almost)
everything from a (possib
people to repair against
'widened' APIs as soon as possible i.e. you'd file a but report against one of
these packages. -- Matthias
On Nov 18, 2013, at 11:56 AM, Greg Hendershott
wrote:
>> In my experience, using plain require and later adding 'except-in' when
I think the proper interface to offer is to separate the interfaces:
-- one function that works on normalized interfaces and for that you use
rgb-color/c
-- other function(s) that work on liberal inputs and clients know they may pay
the cost for double-normalization
On Nov 18, 2013,
On Nov 18, 2013, at 3:15 PM, Norman Ramsey wrote:
>> This is easily doable with a teachpack:
>>
>> 1. how to create a teachpack
>> http://docs.racket-lang.org/htdp/index.html?q=teachpack
>>
>> 2. the key is to document the (a) structure type definition and (b) the
>> data definition you expo
n terms of
> the "three canonical categories" that Matthias described--apologies if I'm
> misrepresenting him/you:
> - changing evaluation order,
> - implementing a data sublanguage, and
> - creating new binding forms.
[That's correct. I used to say 'quoti
(add1
(sub1
((list 1 2 3
application: not a procedure;
expected a procedure that can be applied to arguments
given: '(1 2 3)
arguments...: [none]
context...:
/Users/matthias/plt/racket/collects/racket/private/misc.rkt:87:7
So what language are you specifyi
tep off the beaten path takes people by surprise.
If anyone has time to draft such a document, I'd be happy to play editor.
-- Matthias
Racket Users list:
http://lists.racket-lang.org/users
surveying some of the Rust macros, and roughly categorizing them in terms of
> the "three canonical categories" that Matthias described--apologies if I'm
> misrepresenting him/you:
> - changing evaluation order,
> - implementing a data sublanguage, and
> - creating new
Or match and define-match and define/match if you wish to avoid writing
selectors.
On Nov 25, 2013, at 9:35 AM, "William J. Bowman"
wrote:
> Ben,
>
> I'm not sure what problem you're actually trying to solve, but you may want
> to look at
>
> 0) struct super-type
> http://docs.racket-l
Yes!
On Nov 25, 2013, at 11:31 AM, Greg Hendershott
wrote:
>>> Thanks for the insights. But what does "data sublanguage" mean?
>>>
>> Say you want a three-state machine where the states are labeled 'go, 'stop,
>> 'warning and you use a stream of signals to switch between states say
>> 'b
g about an identifier' -- Matthias
Racket Users list:
http://lists.racket-lang.org/users
Congrats, looks neat! Getting a scribbled pdf from a web site is something
different. Have you considered displaying it as HTML for account holders?
On Dec 2, 2013, at 7:01 AM, Daniel Prager wrote:
> A few hours ago my new start-up -- www.youpatch.com -- came out of stealth
> mode.
>
>
We call it MVC when we must and it is (kind of) baked into the big-bang
approach in the Program by Design curriculum. But we don't use pattern
terminology all that much -- Matthias
On Dec 14, 2013, at 7:05 PM, Geoffrey S. Knauth wrote:
> My son, who I'm afraid/inspire
>
> How do other people create test cases for impure situations?
I have written such a program several years ago (a primitive version) and I
tested it by writing another program that generated tmp directories with
certain characteristics. -- Matthias
Racket Users list:
http://lists.racket-lang.org/users
Yes. There is a (simple) hidden file/directory simulator in the works inside of
2htdp/batch-io for novices to test such things. Nothing you could use but
Robby's right and his message recalled my (aborted) effort from last year --
Matthias
On Dec 22, 2013, at 3:52 PM, Robby Findler
On Dec 23, 2013, at 2:10 PM, Manfred Lotz wrote:
> On Mon, 23 Dec 2013 13:53:05 -0500
> Greg Hendershott
> wrote:
>
>> On Sun, Dec 22, 2013 at 2:49 PM, Neil Van Dyke
>> wrote:
>>> Manfred Lotz wrote at 12/22/2013 01:54 PM:
Or perhaps even better create my directory structure on the fly
For that, you will need to wrap the whole loop because (in-directory ...)
fails, and no, I don't know how to resume this optimized loop:
#lang racket ;; foo.rkt
(define start-dir ".")
;;
(with-handlers (((lambda (x) #t) (lambda (e) (log-warning "in-directory
failed"
(for ([f (in-direc
Sadly, I think you may have to re-implement in-directory (with a recursive
traversal like the one in for.rkt) but use file-or-directory-permission
before you try to go into a subdirectory. -- Matthias
On Dec 23, 2013, at 4:09 PM, Manfred Lotz wrote:
> I had a look into collects/rac
On Dec 23, 2013, at 5:12 PM, Manfred Lotz wrote:
> I think in-directory should be fixed in the long run.
Agreed. -- Matthias
Racket Users list:
http://lists.racket-lang.org/users
parameter. It would generalize this situation
-- Matthias
On Dec 23, 2013, at 5:53 PM, Robby Findler wrote:
> Perhaps in-directory can take an optional parameter that controls whether or
> not to recur?
>
> Robby
>
>
> On Mon, Dec 23, 2013 at 4:42 PM, Matthias Felleisen
This is a bit vague. Can you clarify the question with a concrete example?
On Dec 26, 2013, at 7:45 PM, "Alexander D. Knauth" wrote:
> I want to make contracts on some apply-like functions that check some
> arguments but just passes all the others (including keyword arguments) on to
> a fun
Scribble allows programmers to create their own 'styles' and
within a CSS style you can certainly refer to JS components.
Search for 'style' in the docs (e.g. raco doc style) and peruse
the scribble notion of style.
-- Matthias
On Dec 27, 2013, at 3:36 PM, Martin
> rudimentary expressions.
This might be a MIT misunderstanding about the relationship between Scheme and
the lambda calculus. It is certainly not possible in general and I see no
pragmatic use case for an approximation.
-- Matthias
>
> For example:
>
Do you want to turn it into a package:
(1) http://pkgs.racket-lang.org/
(2) http://docs.racket-lang.org/pkg/?q=package
-- Matthias
On Dec 27, 2013, at 11:03 AM, 钟 wrote:
> I used to write lisp code in emacs and enjoy paredit-mode.I tried to find an
> alternative for DrRacket but
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