2014-08-01 16:11 GMT+02:00 Henrik Johansen <henrik.s.johansen@veloxit.no>:
On 01 Aug 2014, at 3:20 , Serge Stinckwich <serge.stinckwich@gmail.com> wrote:
Dear all,
using Sci-Smalltalk, we found with Natalia that sometimes blocks have strange behavior : https://groups.google.com/forum/#!topic/scismalltalk/HmGpTkzLOdQ
I was able to create a more simpler example using only Pharo. If you try, the following expression, there is no problem:
|state values | values := (1 to: 10000) collect: [ : t| state := { t. t+1. t+2.}]. (1 to: 10000) do:[:i | (values at:i) at:2].
and you do more iterations, an error appears (Instances of SmallInteger are not indexable), because from time to time, an array is replaced by an integer:
|state values | values := (1 to: 100000) collect: [ : t| state := { t. t+1. t+2.}]. (1 to: 100000) do:[:i | (values at:i) at:2].
and if you move the state variable inside the block, it works again :
| values | values := (1 to: 100000) collect: [ : t| |state| state := { t. t+1. t+2.}]. (1 to: 100000) do:[:i | (values at:i) at:2].
Same problem in Pharo 3.0 or Pharo 4.0
Regards,
Speaking of which, when trying to inspect the array, itâs incredibly slow⦠The main reason for this? BasicIndexedEyeElement >> hash ^*super* hash bitXor: index hash
The super implementation? AbstractEyeElement >> hash ^host hash
Guess what the host of an indexedEyeElement is? Thatâs right, the collection⦠So every time it tries to find the cached icon of a line (which is, 10-20 times per refresh cycle depending on the view), it iterates through the 100000 element array to calculate its hashâ¦
Iâd recommend either removing the super call from BasicIndexedEyeElement, or tell the AbstractEyeElement to use the identityHash of its host instead.
Right, current hash is bad and long to compute. I think we should use instead BasicIndexedEyeElement >> hash ^ index hashMultiply host identityHash and index hash may lead to many collisions... What do you think ?
Bonus: It also invokes a #DNU hander every time, since DictionaryValueHolder >> at:ifAbsentPut: is implemented *self* at: key ifAbsent: []. instead of *value* at: key ifAbsent: [].
Your code looks obviously better.
I'm making a slice for that.
Code quality progress. Yay.
Thanks for your contribution. Clement.
Cheers, Henry