On Tue, 13 Apr 2010, Stéphane Ducasse wrote:
Hi levente
may be I did a mistake when I integrated some of your changes. I did not look
at Squeak before posting (because I'm dead).
Now in latest 1.1 several tests for sorted failed because nil is valued while
it should not.
I read the code and I do not really like the aBlockOrNil.
aBlockOrNil is a bit misleading, because it can be anything that understands #value:value:
or it can be nil. This means that the following binary selectors can be used (if you
integrated my changes) instead of blocks: #<= #>= #< #> (or whatever you define
:)).
Using nil is not my idea, I took it from SortedCollection.
Ok
I would prefer to have block all the time.
I was wondering if your original idea was to use nil and if this is the case
why you thought it was
better than just passing a block.
nil is only used for better performance. Since most of the time you only want to
sort by <=.
Here is a simple benchmark which do the same thing, but uses 3 different
"sortBlocks":
| array |
array := (1 to: 100000) asArray shuffle.
[ array sorted: nil ] bench "===> 4.782781984854524 per second.".
[ array sorted: [ :a :b | a <= b ] ] bench "===> 1.496445940890385 per second.".
[ array sorted: #<= ] bench "===> 2.740262282247015 per second."
The above benchmark is a bit unfair, because the vm has special
bytecodes for integer comparisons, so here is the same with strings:
| array |
array := (1 to: 100000) asArray shuffle replace: #asString
[ array sorted: nil ] bench "===> 1.506875117724618 per second.".
[ array sorted: [ :a :b | a <= b ] ] bench "===> 0.718261806428443 per second.".
[ array sorted: #<= ] bench "===> 1.237842617152962 per second.".
I have to look why because for me this is a sad news.
The main cause is that block activation is not cheap.
I hate this nil passing around I prefer cool block.
As soon as we have an inlining jit, the above benchmarks should give the
same results.
Levente
Thanks for the information.
Stef
Levente
sorted
"Return a new sequenceable collection which contains the same elements
as self but its
elements are sorted in ascending order using the #'<=' operator."
^self sorted: [:a :b| a <= b ]
Stef
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