I wrote:
"to-play" MIGHT be a good way to do things, but in many cases
(including the above "accelerate" example) it'll be more natural
to specify a sound as you determine the new world, rather than as
a separate function of the state of the world. It's analogous to
the difference between
_
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Thanks for the answers.
I am very interested in Eli's extension, because my scenario is basically the
same: I teach PLAI, and I am considering to do it with typed racket.
But, type-case is pervasively used in the book, and students like it ;)
-- Éric
On Oct 20, 2011, at 3:39 PM, Sam Tobin-Ho
On Oct 20, 2011, at 5:09 PM, Sam Tobin-Hochstadt wrote:
>
> Unfortunately, Typed Racket doesn't support higher-kinded type
> parameters, which is what you would need here.
That's what we thought/feared.
> If you have an example of how you want to use this where the solution
> I gave earlier does
FWIW, my sound system does all this.
Jay
On Thu, Oct 20, 2011 at 12:51 PM, John Clements
wrote:
>
> On Oct 20, 2011, at 11:42 AM, Matthias Felleisen wrote:
>
>>
>> On Oct 20, 2011, at 2:37 PM, John Clements wrote:
>>
>>> Are you saying that multiple sounds could be occurring at once? This is
>>
On 10/20/2011 12:49 PM, John Clements wrote:
To frame the discussion better, I think that we should probably divide the set of possible sounds into
"momentary" and "ongoing" sounds. If I associate a "pop" with a ball hitting
the ground, I'm probably not interested in thinking about whether the
One of the reasons that overlapping sounds tends to be unpleasant is that most
sound drivers take amplitude input in the range [-1,1]. If you simply add two
sounds that are each in this range, the resulting sound will occasionally have
an amplitude outside the range. The simple (and common) so
On Oct 20, 2011, at 2:49 PM, John Clements wrote:
> I see several (short-term?) problems with this.
>
> 1) To the best of my knowledge, the existing MIDI interfaces don't support
> playing arbitrary sampled sounds, which I think is vital for the kinds of
> games that I imagine students creati
On Thu, Oct 20, 2011 at 2:52 PM, Eric Tanter wrote:
> Thanks Sam,
>
> Actually, that's not what we're after.
>
> In untyped Racket, we have a struct monad:
>
> (struct monad
> (;; A -> M A
> return
> ;; A -> (A -> M B) -> M B
> bind))
>
> Then we have several instantiations (exception, stat
On Thu, Oct 20, 2011 at 3:08 PM, J. Ian Johnson wrote:
> Does typed racket fail to typecheck because cond will return void on negative
> numbers or something more related to exhaustive checking regardless of return
> value?
The former. Since there's no pattern matching in "core" Racket, it's
n
On 10/20/2011 01:27 PM, Jay McCarthy wrote:
On Thu, Oct 20, 2011 at 12:52 PM, Eric Tanter wrote:
Thanks Sam,
Actually, that's not what we're after.
In untyped Racket, we have a struct monad:
(struct monad
(;; A -> M A
return
;; A -> (A -> M B) -> M B
bind))
Then we have sever
On Thu, Oct 20, 2011 at 12:52 PM, Eric Tanter wrote:
> Thanks Sam,
>
> Actually, that's not what we're after.
>
> In untyped Racket, we have a struct monad:
>
> (struct monad
> (;; A -> M A
> return
> ;; A -> (A -> M B) -> M B
> bind))
>
> Then we have several instantiations (exception, sta
Does typed racket fail to typecheck because cond will return void on negative
numbers or something more related to exhaustive checking regardless of return
value?
-Ian
- Original Message -
From: Sam Tobin-Hochstadt
To: Eric Tanter
Cc: Racket Users
Sent: Thu, 20 Oct 2011 14:39:19 -0400
Q: is it possible to test the length of 'momentary' sounds programmatically?
Proposed design:
big-bang accepts another clause:
[sounds pop meow bark]
-- constraint: pop.wav, meow.wav, bark.wav exist in the current
directory
-- constraint: they are momentary sounds
a
Thanks Sam,
Actually, that's not what we're after.
In untyped Racket, we have a struct monad:
(struct monad
(;; A -> M A
return
;; A -> (A -> M B) -> M B
bind))
Then we have several instantiations (exception, state, what-have-you):
(define my-fancy-monad (monad (lambda ...) (lambda .
On Oct 20, 2011, at 11:42 AM, Matthias Felleisen wrote:
>
> On Oct 20, 2011, at 2:37 PM, John Clements wrote:
>
>> Are you saying that multiple sounds could be occurring at once? This is
>> true, but doesn't strike me as a priori unpleasant.
>
> Yes. Supposed your first tick launches Beethov
On Oct 20, 2011, at 6:47 AM, Viera Proulx wrote:
> This is why I think that playing MIDI sounds is the correct model for the
> world.
> On tick we add to the world the sounds that are to be played - they stop
> playing when the next tick starts. (Or, if we control the duration, we
> include th
On Oct 20, 2011, at 2:37 PM, John Clements wrote:
> Are you saying that multiple sounds could be occurring at once? This is true,
> but doesn't strike me as a priori unpleasant.
Yes. Supposed your first tick launches Beethoven's fifth. And the second
prefers Smoke on the Water. They will over
There are basically two options here:
1. If you just use `cond' with no `else', you get a type error when
your cases are not exhaustive. For example:
(: f ((U String Integer) -> Boolean))
(define (f x)
[(string? x) (string=? x "hi")]
[(exact-nonnegative-integer? x) (= x 7)])
This program wil
What I'm saying is that parameter-list* and parameter-list-append do
not seem like things that belong in this API. And it isn't really a
"list" in the sense that it is least fixed point of an inductive
definition like X = nil | (cons parameter X).
Really, there is a new type of data whose purpose
On Oct 20, 2011, at 4:59 AM, Matthias Felleisen wrote:
>
> I think you rather mean the difference between event handlers in Worlds and
> event handlers for Universe Worlds: return a package that may include a sound
> to be played. Sounds depend too much on the exact action you took.
>
> What
On Oct 20, 2011, at 3:53 AM, Stephen Bloch wrote:
>
> On Oct 20, 2011, at 1:20 AM, John Clements wrote:
>
>> I'm pleased to report that the sound library works pretty transparently with
>> the universe teachpack.
>> ...
>> (define (accelerate b)
>> (cond [(and (<= (ball-posn b) 6)
>>
One way is to write an else branch that returns a value that is not the
expected result type. Exhaustion of the elements of a union by previous
branches would cause the typechecker to determine the reachability of that
branch impossible and not report an error.
-Ian
- Original Message -
On Thu, Oct 20, 2011 at 10:45 AM, Eric Tanter wrote:
> Hi,
>
> Is there a way to type a monad?
>
> For example in OCaml:
>
> module type MonadRequirements = sig
> type ‘a t
> val bind : ‘a t -> (‘a -> ‘b t) -> ‘b t
> val return : ‘a -> ‘a t
> end;;
>
> In Typed Racket we can use a polymor
Is there a better data type to tangle them with?
I considered multiple values, but those were cumbersome to save because
(values v ...) isn't a first-class value. Saving and restoring multiple
parameters is the main reason to use a parameter list.
I tried making structs, but that forced me in
At Thu, 20 Oct 2011 09:54:56 -0600,
Neil Toronto wrote:
> I know Blake has wanted these before, so I might throw them into unstable.
Please do. I've wanted these before as well.
Vincent
_
For list-related administrative tasks:
http://lists.racke
Thanks, I'll try that.
Jos
-Original Message-
From: Matthew Flatt [mailto:mfl...@cs.utah.edu]
Sent: jueves, 20 de octubre de 2011 16:58
To: Jos Koot
Cc: users@racket-lang.org
Subject: Re: [racket] port open or closed?
At Thu, 20 Oct 2011 15:35:39 +0200, "Jos Koot" wrote:
> May be I am m
Good. I'm glad we avoided the unknown boogeyman.
But I don't see why you need tangle lists and these things.
Robby
On Thu, Oct 20, 2011 at 10:54 AM, Neil Toronto wrote:
> On 10/20/2011 08:08 AM, Robby Findler wrote:
>>
>> Well, what about the current-namespace? The output ports? It seems
>> dan
On 10/20/2011 08:08 AM, Robby Findler wrote:
Well, what about the current-namespace? The output ports? It seems
dangerous and leak introducing (possibly).
I don't actually have an example where it could cause a problem tho. But
you might try to think thru the ramifications by searing for "curren
At Thu, 20 Oct 2011 15:35:39 +0200, "Jos Koot" wrote:
> May be I am myopic, but I have not found any tools in the docs to check
> whether a port is open or closed. After a port is closed, it may survive. It
> would be handy to have:
>
> 1: a procedure that tells whether or not a port is open.
Th
Hi again,
Is there a mechanism to do an exhaustive type case?
I know I can use (cond [(type-pred? v) ...]
[...])
but of course I have no guarantee that I am exhaustive (and of course, doing
pattern matching to destruct the value would be even nicer).
Basically, I guess
Hi,
Is there a way to type a monad?
For example in OCaml:
module type MonadRequirements = sig
type ‘a t
val bind : ‘a t -> (‘a -> ‘b t) -> ‘b t
val return : ‘a -> ‘a t
end;;
In Typed Racket we can use a polymorphic struct to have the parametrization by
'a and 'b, but is it possible
Well, what about the current-namespace? The output ports? It seems dangerous
and leak introducing (possibly).
I don't actually have an example where it could cause a problem tho. But you
might try to think thru the ramifications by searing for "current-" in the
docs.
Robby
On Tuesday, October 18
This is why I think that playing MIDI sounds is the correct model for the world.
On tick we add to the world the sounds that are to be played - they stop
playing when the next tick starts. (Or, if we control the duration, we include
the information for how many ticks should the sound be played an
May be I am myopic, but I have not found any tools in the docs to check
whether a port is open or closed. After a port is closed, it may survive. It
would be handy to have:
1: a procedure that tells whether or not a port is open.
2: a procedure that given a closed port, reopens it or returns its
But without this bug, I never would have learned how to use 'gdb --pid=...'. ;)
On Thu, Oct 20, 2011 at 8:41 AM, Robby Findler
wrote:
> Perhaps worth pointing out: this PR
>
> http://bugs.racket-lang.org/query/?cmd=view&pr=12280
>
> is an example of how getting an unexpected parameter setting c
Perhaps worth pointing out: this PR
http://bugs.racket-lang.org/query/?cmd=view&pr=12280
is an example of how getting an unexpected parameter setting can lead
to strange behavior.
(This one is a relatively easy one, too; I knew what was going on right away.)
Robby
On Wed, Oct 19, 2011 at 4:
I think you rather mean the difference between event handlers in Worlds and
event handlers for Universe Worlds: return a package that may include a sound
to be played. Sounds depend too much on the exact action you took.
What I dont understand is why John thinks it's simple. I don't understand
On Oct 20, 2011, at 1:20 AM, John Clements wrote:
> I'm pleased to report that the sound library works pretty transparently with
> the universe teachpack.
> ...
> (define (accelerate b)
> (cond [(and (<= (ball-posn b) 6)
> (<= (ball-vel b) 0))
> (begin (play pop)
>
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