August 2011 - Pharo-dev - lists.pharo.org

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by Henrik Sperre Johansen

On 17.08.2011 22:29, Philippe Marschall wrote: > On 17.08.2011 22:17, StÃ©phane Ducasse wrote: >> I wrote >> >> >> cull: anArg >> "Execute the receiver with one or zero argument. >> >> [ 1 + 2 ] cull: 5 >> returns 3 >> [ :x | 1+ 2 + x] cull: 5 >> returns 8 >> " >> ^numArgs = 0 >> ifTrue: [self value] >> ifFalse: [self value: anArg] >> > > So it's like #valueWithPossibleArgument:? Almost. cull: raises error if given blocks with too many args, valueWithPossibleArgument(s): evaluates with the extra args as nil. > Why do we need two methods > that do the same thing? Because valueWithPossibleArguments was there first, and we can't simply remove it. cull is more natural to use in 99.9% of the cases. Also, #cull: protocol only goes up to 4 arguments, mirroring #value: (#cullWithArguments: not being present is mostly an oversight though... ) Cheers, Henry

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by StÃ©phane Ducasse

thanks I will be in the Block chapter I'm revising now :) On Aug 17, 2011, at 10:47 PM, Henrik Sperre Johansen wrote: > On 17.08.2011 22:11, stephane ducasse wrote: >> Hi guys >> >> I would like to get a better system and I would appreciate some comments for these methods. >> >> Stef > Execute receiving block with as many arguments as it requires. > This allows us to write blocks more concisely when we are not necessarily interested in all the available arguments. > > #cull fills the same need as #valueWith[Possible/Enough]Args: , but does not require creating an Array with the arguments, and will raise an error if block has more arguments than provided rather than pass nil in the extraneous ones. > Hence, from where the block is provided, they look almost the same, but where the block is executed, the code is usually cleaner. > > Cheers, > Henry > >

Aug. 17, 2011

[Pharo-project] Concurrency-Oriented Programming in Pharo

by Andrew P. Black

I was looking at some old slides of Joe Armstrong on Concurrency-orinted programming. He set the following challenge: Put N processes in a ring: Send a simple message round the ring M times. Increase N until the system crashes. How long did it take to start the ring? How long did it take to send a message? When did it crash? He gave graphs comparing Erlang, Java and C#. I decided to compare Pharo. Here is what I got; the creation times are PER PROCESS and the messaging times are PER MESSAGE. first run procs creation/Âµs msg/Âµs 200 0 7.0 500 0 9.7 1000 2 15.4 2000 1 21.6 5000 13 31.5 10000 19.9 40.7 20000 46.5 55.4 50000 130.9 98.0 second run procs creation/Âµs msg/Âµs 200 0.0 7.0 500 0.0 10.12 1000 0.0 16.53 2000 1.5 24.26 5000 12.8 32.15 10000 28.1 39.497 20000 58.15 52.0295 50000 75.1 95.581 third run procs creation/Âµs msg/Âµs 200 0.0 7.0 500 0.0 8.6 1000 2.0 11.0 2000 1.0 16.55 5000 10.2 21.76 10000 12.0 49.57 20000 52.35 65.035 50000 91.76 117.1 Each process is a Pharo object (an instance of ERringElement) that contains a counter, a reference to the next ERringElement, and an "ErlangProcess" that is a Process that contains a reference to an instance of SharedQueue (its "mailbox"). The good news is that up to 50k processes, it didn't crash. But it did run with increasing sloth. I can imagine that the increasing process-creation time is due to beating on the memory manager. But why the increasing message-sending time as the number of processes increases? (Recall that exactly one process is runnable at any given time). I'm wondering if the scheduler is somehow getting overwhelmed by all of the non-runable processes that are blocked on Semaphores in SharedQueue. Any ideas? (My code is on Squeaksource in project Erlang. But be warned that there is a simulation of the Erlang "universal server" in there too. To run this code, look for class ErlangRingTest.)

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by Henrik Sperre Johansen

On 17.08.2011 22:11, stephane ducasse wrote: > Hi guys > > I would like to get a better system and I would appreciate some comments for these methods. > > Stef Execute receiving block with as many arguments as it requires. This allows us to write blocks more concisely when we are not necessarily interested in all the available arguments. #cull fills the same need as #valueWith[Possible/Enough]Args: , but does not require creating an Array with the arguments, and will raise an error if block has more arguments than provided rather than pass nil in the extraneous ones. Hence, from where the block is provided, they look almost the same, but where the block is executed, the code is usually cleaner. Cheers, Henry

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by StÃ©phane Ducasse

I prefer execute :) because evaluate looks like you don't run fast and generate possibly assembly on the fly. I stopped long time ago to use evaluate because people also think that Smalltalk is slow because of that evaluation.... silly idiots but they are out there. Stef (Ze mass educator) On Aug 17, 2011, at 10:29 PM, Igor Stasenko wrote: > execute or evaluate? > > > On 17 August 2011 23:17, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: >> I wrote >> >> >> cull: anArg >> "Execute the receiver with one or zero argument. >> >> [ 1 + 2 ] cull: 5 >> returns 3 >> [ :x | 1+ 2 + x] cull: 5 >> returns 8 >> " >> ^numArgs = 0 >> ifTrue: [self value] >> ifFalse: [self value: anArg] >> >> >> >> cull: firstArg cull: secondArg >> "Execute the receiver with two or less arguments. >> >> [ 1 + 2 ] cull: 5 cull: 6 >> returns 3 >> [ :x | 1+ 2 + x] cull: 5 >> returns 8 >> [ :x | 1+ 2 + x] cull: 5 cull: 3 >> returns 8 >> [ :x : y | 1+ y + x] cull: 5 cull: 2 >> returns 8 >> " >> ^numArgs < 2 >> ifTrue: [self cull: firstArg] >> ifFalse: [self value: firstArg value: secondArg] >> >> >> cull: firstArg cull: secondArg cull: thirdArg >> "Execute the receiver with three or less arguments. Check cull:cull: for examples" >> >> ^numArgs < 3 >> ifTrue: [self cull: firstArg cull: secondArg] >> ifFalse: [self value: firstArg value: secondArg value: thirdArg] >> >> >> cull: firstArg cull: secondArg cull: thirdArg cull: fourthArg >> "Execute the receiver with four or less arguments. Check cull:cull: for examples" >> ^numArgs < 4 >> ifTrue: [self cull: firstArg cull: secondArg cull: thirdArg] >> ifFalse: [self value: firstArg value: secondArg value: thirdArg value: fourthArg] >> >> Will add a bug entry >> >> Stef >> > > > > -- > Best regards, > Igor Stasenko AKA sig.

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by Igor Stasenko

this is a convenience methods On 17 August 2011 23:29, Philippe Marschall <kustos(a)gmx.net> wrote: > On 17.08.2011 22:17, StÃ©phane Ducasse wrote: >> I wrote >> >> >> cull: anArg >> Â Â Â "Execute the receiver with one or zero argument. >> >> Â Â Â [ 1 + 2 ] cull: 5 >> Â Â Â Â Â Â Â returns 3 >> Â Â Â [ :x | 1+ 2 + x] cull: 5 >> Â Â Â Â Â Â Â returns 8 >> Â Â Â " >> Â Â Â ^numArgs = 0 >> Â Â Â Â Â Â Â ifTrue: [self value] >> Â Â Â Â Â Â Â ifFalse: [self value: anArg] >> > > > So it's like #valueWithPossibleArgument:? Why do we need two methods > that do the same thing? > > Cheers > Philippe > > > -- Best regards, Igor Stasenko AKA sig.

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by Igor Stasenko

execute or evaluate? On 17 August 2011 23:17, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > I wrote > > > cull: anArg > Â Â Â Â "Execute the receiver with one or zero argument. > > Â Â Â Â [ 1 + 2 ] cull: 5 > Â Â Â Â Â Â Â Â returns 3 > Â Â Â Â [ :x | 1+ 2 + x] cull: 5 > Â Â Â Â Â Â Â Â returns 8 > Â Â Â Â " > Â Â Â Â ^numArgs = 0 > Â Â Â Â Â Â Â Â ifTrue: [self value] > Â Â Â Â Â Â Â Â ifFalse: [self value: anArg] > > > > cull: firstArg cull: secondArg > Â Â Â Â "Execute the receiver with two or less arguments. > > Â Â Â Â [ 1 + 2 ] cull: 5 cull: 6 > Â Â Â Â Â Â Â Â returns 3 > Â Â Â Â [ :x | 1+ 2 + x] cull: 5 > Â Â Â Â Â Â Â Â returns 8 > Â Â Â Â [ :x | 1+ 2 + x] cull: 5 cull: 3 > Â Â Â Â Â Â Â Â returns 8 > Â Â Â Â [ :x : y | 1+ y + x] cull: 5 cull: 2 > Â Â Â Â Â Â Â Â returns 8 > Â Â Â Â " > Â Â Â Â ^numArgs < 2 > Â Â Â Â Â Â Â Â ifTrue: [self cull: firstArg] > Â Â Â Â Â Â Â Â ifFalse: [self value: firstArg value: secondArg] > > > cull: firstArg cull: secondArg cull: thirdArg > Â Â Â Â "Execute the receiver with three or less arguments. Check cull:cull: for examples" > > Â Â Â Â ^numArgs < 3 > Â Â Â Â Â Â Â Â ifTrue: [self cull: firstArg cull: secondArg] > Â Â Â Â Â Â Â Â ifFalse: [self value: firstArg value: secondArg value: thirdArg] > > > cull: firstArg cull: secondArg cull: thirdArg cull: fourthArg > Â Â Â Â "Execute the receiver with four or less arguments. Check cull:cull: for examples" > Â Â Â Â ^numArgs < 4 > Â Â Â Â Â Â Â Â ifTrue: [self cull: firstArg cull: secondArg cull: thirdArg] > Â Â Â Â Â Â Â Â ifFalse: [self value: firstArg value: secondArg value: thirdArg value: fourthArg] > > Will add a bug entry > > Stef > -- Best regards, Igor Stasenko AKA sig.

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by Philippe Marschall

On 17.08.2011 22:17, StÃ©phane Ducasse wrote: > I wrote > > > cull: anArg > "Execute the receiver with one or zero argument. > > [ 1 + 2 ] cull: 5 > returns 3 > [ :x | 1+ 2 + x] cull: 5 > returns 8 > " > ^numArgs = 0 > ifTrue: [self value] > ifFalse: [self value: anArg] > So it's like #valueWithPossibleArgument:? Why do we need two methods that do the same thing? Cheers Philippe

Aug. 17, 2011

Re: [Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by StÃ©phane Ducasse

I wrote cull: anArg "Execute the receiver with one or zero argument. [ 1 + 2 ] cull: 5 returns 3 [ :x | 1+ 2 + x] cull: 5 returns 8 " ^numArgs = 0 ifTrue: [self value] ifFalse: [self value: anArg] cull: firstArg cull: secondArg "Execute the receiver with two or less arguments. [ 1 + 2 ] cull: 5 cull: 6 returns 3 [ :x | 1+ 2 + x] cull: 5 returns 8 [ :x | 1+ 2 + x] cull: 5 cull: 3 returns 8 [ :x : y | 1+ y + x] cull: 5 cull: 2 returns 8 " ^numArgs < 2 ifTrue: [self cull: firstArg] ifFalse: [self value: firstArg value: secondArg] cull: firstArg cull: secondArg cull: thirdArg "Execute the receiver with three or less arguments. Check cull:cull: for examples" ^numArgs < 3 ifTrue: [self cull: firstArg cull: secondArg] ifFalse: [self value: firstArg value: secondArg value: thirdArg] cull: firstArg cull: secondArg cull: thirdArg cull: fourthArg "Execute the receiver with four or less arguments. Check cull:cull: for examples" ^numArgs < 4 ifTrue: [self cull: firstArg cull: secondArg cull: thirdArg] ifFalse: [self value: firstArg value: secondArg value: thirdArg value: fourthArg] Will add a bug entry Stef

Aug. 17, 2011

[Pharo-project] what are the comments of cull: cull: cull:cull: and friends?

by stephane ducasse

Hi guys I would like to get a better system and I would appreciate some comments for these methods. Stef

Aug. 17, 2011