#lang racket
(define-syntax (fun stx)
(syntax-case stx ()
((fun body rest ...)
(with-syntax ((x (datum->syntax #'body 'x))
(y (datum->syntax #'body 'y))
(z (datum->syntax #'body 'z)))
(let ([y? (identifier-binding #'y)]
[z? (iden
Inspired by the Game of Life tweet challenge (that was seriously cool,
for a geeky definition of "cool"), I compressed a program that
calculates pi to arbitrary precision. By my count, this is 132
characters, after removing comments and extra whitespace:
;; Computes a converging approximation
On 02/22/2012 05:35 PM, Sam Tobin-Hochstadt wrote:
You're very close -- you just need to give inference a little more
help. This definition works:
(: card* (All (a) ((Set* a) -> Hereditary-Set)))
(define (card* A)
((inst card (U a (Set* a))) A))
Ah, excellent. Thanks!
My brain was injur
It's probably not what you think. :)
Jay and I just submitted a paper to FLOPS (conditionally accepted) that
defines an untyped lambda calculus, lambda-ZFC, that contains a model of
set theory and primitive set operations. The basic idea is to "port"
constructions from contemporary math into l
I am new to macro writing and am trying to do the following:
(fun body ...)
=> (lambda (x) body ...)
or (lambda (x y) body ...)
or (lambda (x y z) body ...)
where x, y, z are taken from the scope of body.
Right now, I am just trying to use case-lambda to switch between
these. I guess I am tryin
So are you going to reconstruct all of set theory in TR, including ordinals up
to epsilon0 and cardinals below aleph-something?
On Feb 22, 2012, at 7:35 PM, Sam Tobin-Hochstadt wrote:
> You're very close -- you just need to give inference a little more
> help. This definition works:
>
> (:
You're very close -- you just need to give inference a little more
help. This definition works:
(: card* (All (a) ((Set* a) -> Hereditary-Set)))
(define (card* A)
((inst card (U a (Set* a))) A))
My brain was injured thinking about those types, though. :)
On Wed, Feb 22, 2012 at 7:11 PM, Neil
I'd like to use the same functions to operate on both "flat" container
types and arbitrarily nested container types. More precisely, I want a
type for `Set*' that allows this program otherwise unchanged:
#lang typed/racket
(struct: Empty-Set ())
(struct: (a) Opaque-Set ([error-thunk : (-> a)]
On 02/22/2012 03:34 PM, Sam Tobin-Hochstadt wrote:
On Wed, Feb 22, 2012 at 3:51 PM, Neil Toronto wrote:
The following program types without trouble:
#lang typed/racket
(struct: (a) Foo ())
(: make-foo (All (a) (a -> (Foo a
(define (make-foo x)
(Foo))
(ann (make-foo 1) : (Foo String)
On Wed, Feb 22, 2012 at 3:51 PM, Neil Toronto wrote:
> The following program types without trouble:
>
>
> #lang typed/racket
>
> (struct: (a) Foo ())
>
> (: make-foo (All (a) (a -> (Foo a
> (define (make-foo x)
> (Foo))
>
> (ann (make-foo 1) : (Foo String))
>
> It doesn't seem like it should,
The following program types without trouble:
#lang typed/racket
(struct: (a) Foo ())
(: make-foo (All (a) (a -> (Foo a
(define (make-foo x)
(Foo))
(ann (make-foo 1) : (Foo String))
It doesn't seem like it should, though. If this is the right behavior,
is there a way to get a `Foo' pa
Indexes are used by the file server to turn a directory request into a
file request if the file exists.
What you want is some default behavior if there is no other handler
for a request, you could do that with a lift [1] dispatcher where the
procedure was just (lambda (req) (redirect-to "/index.rk
Thanks Rodolfo,
I did some further experiments which confirm your results. I noticed that
results vary quite a bit run to run so I ran several times from clean and
took the median:
prime-pi/acc 400 with original make-coroutine:
cpu time: 2808 real time: 2879 gc time: 1000
prime-pi/acc 40
When I run this code:
#lang typed/racket
(: ten? (Integer -> Boolean))
(define (ten? x)
(= x 10))
(declare-refinement ten?)
(define-type Ten (Refinement ten?))
I get this error:
Type Checker: cannot declare refinement for non-predicate Nothing in:
(Refinement ten?)
But the test in "ref
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hi Roelof,
On 22-02-12 12:49, Roelof Wobben wrote:
> I found a working solution but I wonder if there is a better way
> to achieve the answer in the Beginning Student modus.
Allow me to propose an alternative solution and perform some
constructive cr
Hello Joe,
2012/2/22 Joe Gilray
> Hi Matthew,
>
> Thanks for your help. I really can't even pretend to understand the
> make-coroutine code but this is what I'm seeing:
>
> Original make-coroutine, without stream-ref pre-call => out of memory
> (1GB) when running (prime-pi 50)
>
I tried
Op 22-2-2012 9:58, Roelof Wobben schreef:
Thanks,
I have now a answer to my question.
I will debug my programm with check-expect and wil take a look at the
second edition.
Roelof
Op 21-2-2012 22:40, Stephen Bloch schreef:
On Feb 21, 2012, at 3:18 PM, Roelof Wobben wrote:
Op 21-2-2012 2
Neil and all, hello.
On 2012 Feb 21, at 21:59, Neil Van Dyke wrote:
> Neil Van Dyke wrote at Sun, 19 Feb 2012 05:40:56 -0500 (EST):
>> Even Brown U. and the few Seven Sisters that I checked seem to use
>> "freshmen" in current official communications. (Not a lot of
>> "freshwomyn" in Google.)
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