Hi, the other day I was at a conference in London and learned Scala.
As my first program I translated a favourite fractal tree program
(which I stole from: http://marblemice.com/2009/04/26/clojure-fractal-tree/).
The programs are almost exactly the same in the two languages.
The Scala version
Oops, sorry, I thought my post was stuck in the moderation queue and
have only just noticed the replies while browsing through the list
history! Thanks to everyone who replied.
Your version looks to be about six times faster than mine was. Thanks
ever so much!
In fact I wouldn't have noticed the
Hi, am I doing something wrong here?:
user= (clojure-version)
1.4.0
user= (use 'clojure.test)
nil
user= (is ((fn[x] x) 1) 1)
1
user= (are [ x y ] (= x y) ((fn[x] x) 1) 1)
StackOverflowError clojure.core/map/fn--4087 (core.clj:2426)
user= (macroexpand '(are [ x y ] (= x y) ((fn[x] x) 1) 1))
Thanks Guys, I'll avoid the are macro.
Any ideas why this doesn't work?:
user= (use 'clojure.test)
nil
user= (use 'clojure.test.tap)
nil
user= (deftest a (is true))
#'user/a
user= (run-tests)
Testing user
Ran 1 tests containing 1 assertions.
0 failures, 0 errors.
{:type :summary, :pass 1,
Hi, I'm getting an unexpected exception trying to do unchecked
arithmetic:
user= (def seed1 25214903917)
#'user/seed1
user= (type seed1)
java.lang.Long
user= (type 25214903917)
java.lang.Long
user= (unchecked-multiply seed1 0x5DEECE66D)
ArithmeticException integer overflow
Great, thanks!
So if one is an object and one is a primitive is one of these not true?
user= (type seed1)
java.lang.Long
user= (type 25214903917)
java.lang.Long
Cheers, John.
On Wednesday, February 20, 2013 11:44:44 PM UTC, Herwig Hochleitner wrote:
I agree that unchecked-multiply
So, something like: (type 23) the reader makes a list of a symbol and a
primitive, the evaluator evals to get a generic function and a primitive,
then tries to apply the generic function to the primitive, can't find a
primitive version, so boxes the primitive to an object and tries again, and
Hi,
Laziness makes my head hurt.
Is there any reason this is desirable behaviour?:
user= (clojure-version)
1.4.0
user= (reduce (fn [a b] (map + [1 1] a)) [1 1] (range 1000))
(1001 1001)
user= (reduce (fn [a b] (map + [1 1] a)) [1 1] (range 1500))
StackOverflowError
Hi Guys,
I haven't used Clojure for a year or so (I was busy in C and Verilog),
but I still love it and would like to use it.
I'm going to write a web app. I want to ask users to answer multiple
choice questions and time their responses. I'd like them to be able to
easily make accounts (the
with Datomic and
Noir. I listed SQL and Mongo just in case :-) Feel free to ask me more here
or off-list if you like!
On Tuesday, November 20, 2012 3:29:19 PM UTC+2, John Lawrence Aspden wrote:
Hi Guys,
I haven't used Clojure for a year or so (I was busy in C and Verilog),
but I still love
to the various tutorials.
On 20/11/2012, John Gabriele jmg3...@gmail.com wrote:
On Tuesday, November 20, 2012 8:29:19 AM UTC-5, John Lawrence Aspden wrote:
My intutition is telling me to use Python and Flask, but my heart is
telling me to use Clojure and some framework, but I don't know what is
best
Hi Guys,
I'm trying to memoize a fairly complicated double recursion, and it's
blowing stack after not terribly many calls.
I've reduced the problem to a simple test case, summing from 1 to n :
user= (clojure-version)
1.5.1
user= (def gauss-recurse (fn [n] (if ( n 1) 0 (+ n (gauss-recurse
, Sep 22, 2013 at 8:19 AM, John Lawrence Aspden
asp...@googlemail.com javascript: wrote:
Hi Guys,
I'm trying to memoize a fairly complicated double recursion, and it's
blowing stack after not terribly many calls.
I've reduced the problem to a simple test case, summing from 1 to n :
user
Ah, it turns out that adding this
:jvm-opts [-Xss50M]
to project.clj
gets me about 25000 memoized self-calls, so that will do.
Last time I had to worry about stack size I was programming an 8051 . I'd
forgotten!
Cheers, John.
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the stack size should give
me as much recursion as a man could reasonably need.
John.
On Monday, September 23, 2013 2:13:12 PM UTC+1, Chris Perkins wrote:
On Sunday, September 22, 2013 5:28:37 PM UTC-6, John Lawrence Aspden wrote:
This recursion limit really is quite nasty. I could probably
Reeves wrote:
On 23 September 2013 00:28, John Lawrence Aspden
asp...@googlemail.comjavascript:
wrote:
Nice, but it won't work for me, since I'm trying to avoid computing all
the values in the table, and so I can't use the pump-priming approach. I
don't know what values I'm going to need
Jim, increasing the stack size solved the problem in so far as it allowed
the code to run (I needed a tree depth of 2000), but then it just sat and
churned for hours and ran down the battery bank on my narrowboat, so I
killed it.
This morning I bit the bullet and got the clojure program to
Puzzler, thanks for all your excellent ideas!
I get the impression that you're as troubled as I am by the brokenness of
recursion, but it looks like it can be worked around.
A bit of memory thrown at the JVM stack combined with a better memoization
technique should work in most of the cases
These behave differently in 1.6 with respect to printing the empty list:
(clojure.pprint/print-table (list {:a 1 :b 2 :c '()}))
| :a | :b | :c |
|++-|
| 1 | 2 | clojure.lang.PersistentList$EmptyList@1 |
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