Hi,
2009/6/14 CuppoJava patrickli_2...@hotmail.com:
I actually really do like the reduce with early exit abstraction.
Because ultimately, that's what the question is. It's a reduce with
optimization.
However, I feel that Laurence's reduce is a little too specific. The
early exit condition
2009/6/14 James Reeves weavejes...@googlemail.com:
On Jun 13, 9:57 pm, Laurent PETIT laurent.pe...@gmail.com wrote:
The filter and map functions produce lazy seqs, so the sequence is
only walked once.
Well, isn't walking 3 different sequences 1 time almost equivalent (in
terms of
On Jun 13, 4:17 pm, Laurent PETIT laurent.pe...@gmail.com wrote:
So it really seems to me that the missing abstraction, here, is being
able to do a reduce over the list of pixels, and being able, from the
reduction function, to quit the reduction early.
A lazy right fold[1] allows
On Jun 13, 4:39 pm, Laurent PETIT laurent.pe...@gmail.com wrote:
Hi,
Well, the array is iterated once by map, the new seq created by map is
iterated once by filter, and the new seq created by filter is iterated
once by count, so right, I should have written : 3 walks of seqs of
the size of
Laurent, I think this is a close variant of the early exiting reduce
function you proposed:
(defn reduce-bail [f pred? val col]
(let [s (seq col)]
(if s
(if (pred? val)
(recur f pred? (f val (first s)) (next s))
val)
On Jun 14, 5:04 am, Max Suica max.su...@gmail.com wrote:
(defn interesting? [pixels in-range? count]
(let [p-count (reduce-bail (fn [c p] (if (in-range? p) (inc c) c))
(partial count) 0 pixels)]
[( = count yummy-pix-count) p-count]))
Shoot: s/[( = count yummy-pix-count) p-count]))/[( =
A lazy right fold[1] allows short-circuiting, so here's one attempt:
Wow, that made my head explode.
Some points:
1) That's not exatly foldr, as (foldr + 0 [range 100]) ought to work
2) Foldr is not tail recursive nor can you really call an anamorphism
lazy
3) Never the less you did it,
I'm sorry, folds are catamorphisms, while stuff like (repeatedly f) or
(repeat n x) are anamorphisms, and can certainly be lazy.
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On Jun 14, 5:31 am, Max Suica max.su...@gmail.com wrote:
A lazy right fold[1] allows short-circuiting, so here's one attempt:
Wow, that made my head explode.
Some points:
1) That's not exatly foldr, as (foldr + 0 [range 100]) ought to work
Agreed, having to write that as
(foldr (fn [x
On Jun 14, 6:37 am, Wrexsoul d2387...@bsnow.net wrote:
On Jun 13, 11:07 pm, James Reeves weavejes...@googlemail.com wrote:
For instance, lets say I want to return a lazy list of all the lines
in all the files in a directory tree:
(use '(clojure.contrib java-utils
I just wanted to report back that StringTemplate proved to be the
perfect solution.
I also wanted to recommend Terrence Parr's (the creator and ANTLR and
StringTemplate) new book Language Design Patterns from The Pragmatic
Programmers for anyone doing parsing and code generation. It is an
On Jun 14, 4:37 am, Wrexsoul d2387...@bsnow.net wrote:
Seems to me that unless you completely consume the sequence, it will
leak a file handle.
That's true, but that's a problem that affects all seqs. There's no
current way to mark a seq that comes from a stream as being discarded
or closed,
I've been playing around with rewriting some Java code in Clojure and
did some simple benchmarking in the process. In this case, there's a
huge disparity in the performance numbers between the two languages,
and I'm wondering what the cause may be. The program rotates a string
from , aaab,
On Jun 14, 4:40 am, Wrexsoul d2387...@bsnow.net wrote:
What I miss is foo-array for foo not in #{int long float double},
particularly for (= foo byte).
You can use (make-array Byte/TYPE size) and (into-array Byte/TYPE byte-
coll).
- James
--~--~-~--~~~---~--~~
On Jun 14, 3:28 am, tmountain tinymount...@gmail.com wrote:
java.lang.IllegalArgumentException: No matching method found:
setCharAt for class java.lang.StringBuilder (NO_SOURCE_FILE:0)
user= (type (char \a))
java.lang.Character
; should be char?
You could try: (.charValue \a)
- James
That doesn't work either. It appears this isn't an issue with Java 6,
but that doesn't help me on my PPC powerbook, which is apparently
stuck with the Java 5 JRE for the foreseeable future.
Thanks,
Travis
On Jun 14, 10:44 am, James Reeves weavejes...@googlemail.com wrote:
On Jun 14, 3:28 am,
On Jun 14, 7:00 pm, tmountain tinymount...@gmail.com wrote:
I've been playing around with rewriting some Java code in Clojure and
did some simple benchmarking in the process. In this case, there's a
huge disparity in the performance numbers between the two languages,
and I'm wondering what
On Jun 14, 9:39 am, James Reeves weavejes...@googlemail.com wrote:
Okay, but don't underestimate the power of higher level functions. I
don't know whether it would apply to your code, but the repeatedly
function can be used to create a lazy seq from a function with side-
effects.
For
Thanks for your answers.
I read the thread and understood why I don't get my
IllegalArgumentException but a new RuntimeException that wrapps it.
But I don't understand what the reason is to create a new
RuntimeException (stack tracing?) knowing that IllegalException is a
subclass of
kedu Travis,
(defn base26 [ n]
(let [seed-string
s (new StringBuilder seed-string)]
(loop [ pos (- (count seed-string) 1)
x n]
(if (and ( pos 0)( x 0))
(do (. s setCharAt pos (char (+ (int \a) (mod x 26
(recur (- pos 1) (/ x 26)
(. s
On Jun 14, 6:32 pm, Wrexsoul d2387...@bsnow.net wrote:
I wrote super-lazy-seq because repeatedly can't generate a finite
sequence. It just spat out
(File1 File2 File3 File4 nil nil nil nil nil nil nil ...
Well, you could wrap it in take-while:
(defn custom-lazy-seq [stream]
markgunnels,
Have you used clojure and StringTemplate to do something? If so, I would
like to tap your knowledge there.
Regards,
Emeka
On Sun, Jun 14, 2009 at 1:36 PM, markgunnels markgunn...@gmail.com wrote:
I just wanted to report back that StringTemplate proved to be the
perfect
If I run this code:
(def ibounds 100)
(let [arlist (new java.util.ArrayList ibounds)]
(dotimes [i ibounds]
(.add arlist 0))
(time (dotimes [x 100]
(dotimes [i ibounds]
(.set arlist i 1)
(let [arlist (make-array Integer/TYPE ibounds)]
In the example below 256 clients threads put a byte (0-255) to server-
socket reference var items,
then connect to server-socket, write the same byte to socket stream
and close the connection.
The server connections threads reads a byte from the socket stream and
remove it from the var items.
At
On Jun 13, 2009, at 10:46 PM, Stephen C. Gilardi wrote:
user= (.setCharAt s 0 \c)
java.lang.IllegalArgumentException: Can't call public method of non-
public class: public void
java.lang.AbstractStringBuilder.setCharAt(int,char) (NO_SOURCE_FILE:0)
I'm not sure why.
StringBuilder extends
On Jun 14, 2:53 pm, James Reeves weavejes...@googlemail.com wrote:
On Jun 14, 6:32 pm, Wrexsoul d2387...@bsnow.net wrote:
I wrote super-lazy-seq because repeatedly can't generate a finite
sequence. It just spat out
(File1 File2 File3 File4 nil nil nil nil nil nil nil ...
Well, you
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