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Re: [Pharo-users] looking for another iterator :)

by Evan Donahue

It is also worth mentioning that there is now also the Cons library available through the Pharo6 catalog browser. Cons is a lazy linked list that can be used like a normal linked list, but can also be used as an iterator over streams or infinite-sequence-generating blocks, using the usual Pharo collections API. myStream := (1 to: 100) readStream. (myStream asCons take: 5) do: [ ... ]. Due to the laziness, Cons, like Clojure's transducers, doesn't build intermediate representations, so things like #selectThenCollect: aren't necessary. (myList select: sBlock) collect: cBlock just creates an iterator and never actually creates the whole list, although you can still treat it like a list with #first, #allButRest, etc. The code is stable and in use in several of my projects. Evan -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Jan. 26, 2018

Re: [Pharo-users] looking for another iterator :)

by Richard O'Keefe

I thought about that for my own Smalltalk, but then realised that I didn't know whether #upTo:timesSelect: was bounding the number of elements *considered* or the number of elements in the *result*, and I could argue either way. Arguably the cleanest way would be to have something like (LimitedEnumerableAdapter on: collection limit: anInteger) do: aBlock select: aBlock collect: aBlock ... *any* existing or new collection method. On 22 January 2018 at 11:46, James Foster <Smalltalk(a)jgfoster.net> wrote: > Since âatMax:â doesnât seem as clear to me, Iâd prefer âupToMax:â or > âwithMax:â or (especially) the following: > > upTo: anInteger timesDo: aBlock > upTo: anInteger timesSelect: aBlock > upTo: anInteger timesCollect: aBlock > > James Foster > > > On Jan 21, 2018, at 8:56 AM, Stephane Ducasse <stepharo.self(a)gmail.com> > wrote: > > > > I thought about something like that... > > > > SequenceableCollection >> atMax: numberOfItems do: aBlock > > "Execute the iteration with at the maximum numberOfItems. If the > > receiver contains less than numberOfItems iterate them all." > > 1 to: (numberOfItems min: self size) do: [:index | aBlock value: > > (self at: index)] > > > > This is an abstraction that we need to treat some samples. > > > > Stef > > > > On Sun, Jan 21, 2018 at 5:47 PM, Stephane Ducasse > > <stepharo.self(a)gmail.com> wrote: > >> Hi Ben and Clement > >> > >> I have a collection (a dictionary in my case) and I want to get > >> maximum 5 bindings out of it and iterate on them. > >> I want keysAndValuesDo: or do: but only up to 5 elements. > >> > >> aDict atMax: 5 do: [:each | ] > >> > >> So I learned from:to:do: > >> > >> aCollection atMax: 5 do: [:each | ] > >> > >> Does it make sense? > >> > >> Stef > >> > >> On Sun, Jan 21, 2018 at 1:16 PM, ClÃ©ment Bera <bera.clement(a)gmail.com> > wrote: > >>> I don't think we do. Do you need it on SequenceableCollection or > >>> HashedCollection too ? > >>> > >>> Recently I was trying to iterate over the first N elements of a > collection > >>> and since there was no #first:do: I used #from:to:do:. I guess you > could use > >>> that too: > >>> > >>> aCollection from: 1 to: (aCollection size min: 1000) do: aBlock > >>> > >>> Which guarantees you iterate at max over 1000 elements. But that API is > >>> SequenceableCollection specific. > >>> > >>> On Sun, Jan 21, 2018 at 11:44 AM, Ben Coman <btc(a)openinworld.com> > wrote: > >>>> > >>>> On 21 January 2018 at 18:36, Stephane Ducasse < > stepharo.self(a)gmail.com> > >>>> wrote: > >>>>> Hi > >>>>> > >>>>> I would like to iterate at max on a certain amount of elements in a > >>>>> collection. > >>>>> And I was wondering if we have such iterator. > >>>> > >>>> I'm not clear what functionality your asking for. Could you present > >>>> it as code & result if you assumed the iterator you want was > >>>> available? > >>>> > >>>> cheers -ben > >>>> > >>> > >>> > >>> > >>> -- > >>> ClÃ©ment BÃ©ra > >>> Pharo consortium engineer > >>> https://clementbera.wordpress.com/ > >>> BÃ¢timent B 40, avenue Halley 59650 Villeneuve d'Ascq > > > > > > >

Jan. 26, 2018

Re: [Pharo-users] looking for another iterator :)

by Richard O'Keefe

My own Smalltalk has these: Enumerable methods for: 'enumerating' limit: n do: aBlock "Pass elements of the receiver to aBlock one at a time, as for #do:, but stop after n elements. n must be a non-negative SmallInteger. Which elements you get is for the receiver to decide." |count| n < 1 ifTrue: [ n = 0 ifTrue: [^self]ifFalse: [self pvtCountError: n]]. count := 0. self do: [:each | aBlock value: each. (count := count + 1) < n ifFalse: [^self]]. AbstractKeyedCollection methods for: 'enumerating' limit: n keysAndValuesDo: aBlock "Pass keys and corresponding values of the receiver to aBlock one at a time, as for #keysAndValuesDo:, but stop after n elements. See #limit:do:." |count| n < 1 ifTrue: [ n = 0 ifTrue: [^self]ifFalse: [self pvtCountError: n]]. count := 0. self keysAndValuesDo: [:key :value | aBlock value: key value: value. (count := count + 1) < n ifFalse: [^self]]. Enumerable is the superclass of Collection; it doesn't cover streams but does cover 2- and 3-dimensional arrays. AbstractKeyedCollection covers both dictionaries and sequences. Since they only depend on #do: and #keysAndValuesDo: respectively, they should fit nicely into some sort of Trait(s). I gave a great deal of thought to the names, and decided on "limit" since it is already in use in a similar sense in things like LimitedOutputStream or #printStringLimitedTo:. I did consider #do:limitedTo: and #keysAndValuesDo:limitedTo: which would be more consistent with #streamContents:limitedTo:, but "heavy" things like blocks really work better at the end.

Jan. 26, 2018

Re: [Pharo-users] How to declare a do:[] loop for a matrix to read and acces its elements?

by Richard O'Keefe

Sorry about the late reply, but I've been away on holiday. You wrote "Im not sure is the gameworld should grow inifitly. In the ruleset on wikipedia there is a fixed board size. The smallest one is 3*3 but I could implement is as one possible size to select from." It's not your decision. Conway's Life simply *is* defined for an infinite world. Without that, it wouldn't be Turing-universal, as it is. The first sentence in the Rules section begins "The universe of the Game of Life is an infinite two-dimensional orthogonal <https://en.wikipedia.org/wiki/Orthogonal> grid". The ruleset on the Wikipedia page does NOT have a fixed size. The examples are shown just big enough to contain all the live cells, but that is another matter. There are four things you can do when emulating a game on a grid: (1) STOP when you hit the edge, deliberately or by crashing. (2) ERR by pretending everything outside is dead. The program does not stop, it just stops giving right answers. (3) REDEFINE the world to be a toroidal space instead of an infinite one. Again, this changes the rules enough to count as a different game. (4) GROW the world. Allocate a new bigger world and copy the old one across. But the best way to deal with limitations is to avoid building them into the program in the first place. It's a bit like concurrency. It took a while before I realised that "how do I add concurrency to my programs" was the wrong question and that I should have been asking "how do I learn to stop adding sequentiality to my programs?"

Jan. 26, 2018

Re: [Pharo-users] Voyage and Instance Mode

by Esteban Lorenzano

> On 25 Jan 2018, at 23:24, Dominique Dartois <dom(a)dartois.org> wrote: > > Thanks Esteban. > I was fooled by the doc : "In instance mode, the first argument is always the repository on which to performed the operation"... > Well, not really, but the object to store. yeah, it should say: the receiver. > > Regards > > 2018-01-25 23:07 GMT+01:00 Esteban Lorenzano <estebanlm(a)gmail.com <mailto:estebanlm@gmail.com>>: > > > > On 25 Jan 2018, at 23:03, Dominique Dartois <dom(a)dartois.org <mailto:dom@dartois.org>> wrote: > > > > Hello all. > > > > I'am learning to use Voyage by trying the examples in the Voyage doc (in the Enterprise Pharo book). > > I read "By default, Voyage works in instance mode". > > If I run the example in instance mode, I get an error via the debugger. > > > > |repo anAssociation| > > repo := VOMemoryRepository new. > > anAssociation := #answer -> 42. > > anAssociation save: repo. > > repo save: anAssociation :) > > cheers! > Esteban > > > ==> "Instance of Association did not understand #save:" > > > > What am I doing wrong? > > > > -- > > Dominique > > > > > > -- > Dominique

Jan. 25, 2018

Re: [Pharo-users] Voyage and Instance Mode

by Dominique Dartois

Thanks Esteban. I was fooled by the doc : "In instance mode, the first argument is always the repository on which to performed the operation"... Well, not really, but the object to store. Regards 2018-01-25 23:07 GMT+01:00 Esteban Lorenzano <estebanlm(a)gmail.com>: > > > > On 25 Jan 2018, at 23:03, Dominique Dartois <dom(a)dartois.org> wrote: > > > > Hello all. > > > > I'am learning to use Voyage by trying the examples in the Voyage doc (in > the Enterprise Pharo book). > > I read "By default, Voyage works in instance mode". > > If I run the example in instance mode, I get an error via the debugger. > > > > |repo anAssociation| > > repo := VOMemoryRepository new. > > anAssociation := #answer -> 42. > > anAssociation save: repo. > > repo save: anAssociation :) > > cheers! > Esteban > > > ==> "Instance of Association did not understand #save:" > > > > What am I doing wrong? > > > > -- > > Dominique > > > -- Dominique

Jan. 25, 2018

Re: [Pharo-users] Voyage and Instance Mode

by Esteban Lorenzano

> On 25 Jan 2018, at 23:03, Dominique Dartois <dom(a)dartois.org> wrote: > > Hello all. > > I'am learning to use Voyage by trying the examples in the Voyage doc (in the Enterprise Pharo book). > I read "By default, Voyage works in instance mode". > If I run the example in instance mode, I get an error via the debugger. > > |repo anAssociation| > repo := VOMemoryRepository new. > anAssociation := #answer -> 42. > anAssociation save: repo. repo save: anAssociation :) cheers! Esteban > ==> "Instance of Association did not understand #save:" > > What am I doing wrong? > > -- > Dominique

Jan. 25, 2018

Voyage and Instance Mode

by Dominique Dartois

Hello all. I'am learning to use Voyage by trying the examples in the Voyage doc (in the Enterprise Pharo book). I read "By default, Voyage works in instance mode". If I run the example in instance mode, I get an error via the debugger. |repo anAssociation| repo := VOMemoryRepository new. anAssociation := #answer -> 42. anAssociation save: repo. ==> "Instance of Association did not understand #save:" What am I doing wrong? -- Dominique

Jan. 25, 2018

Download pillar image -> Error 403: Forbidden

by HernÃ¡n Morales Durand

I am following the Publishing Pillar Booklet guide from here https://github.com/SquareBracketAssociates/Booklet-PublishingAPillarBooklet $ git clone git@github.com:SquareBracketAssociates/Booklet-PublishingAPillarBooklet.git $ cd Booklet-PublishingAPillarBooklet/ $ wget https://raw.githubusercontent.com/pillar-markup/pillar/master/download.sh $ chmod +x download.sh $ ./download.sh --2018-01-25 17:56:32-- http://get.pharo.org/vm50 Resolving get.pharo.org (get.pharo.org) 164.132.235.17 Connecting to get.pharo.org (get.pharo.org)|164.132.235.17|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 5819 (5.7K) Saving to: 'STDOUT' 0K ..... 100% 371K=0.02s 2018-01-25 17:56:33 (371 KB/s) - written to stdout [5819/5819] Downloading the latest pharoVM: http://files.pharo.org/get-files/50/pharo-win-stable.zip pharo-vm/Pharo.exe Downloading PharoV50.sources: http://files.pharo.org/get-files/50/sources.zip Creating starter scripts pharo and pharo-ui --2018-01-25 17:57:21-- https://github.com/pillar-markup/pillar/releases/download/50/Pillar-deploym… Resolving github.com (github.com) 192.30.253.112, 192.30.253.113 Connecting to github.com (github.com)|192.30.253.112|:443... connected. HTTP request sent, awaiting response... 302 Found Location: https://github-production-release-asset-2e65be.s3.amazonaws.com/41843105/f4… [following] --2018-01-25 17:57:23-- https://github-production-release-asset-2e65be.s3.amazonaws.com/41843105/f4… Resolving github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com) 54.231.115.35 Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|54.231.115.35|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 18482449 (18M) [application/octet-stream] Saving to: 'imageLn5zD.zip' imageLn5zD.zip 10%[=> ] 1.88M 502 B/s in 8m 7s 2018-01-25 18:15:45 (3.94 KB/s) - Read error at byte 1966661/18482449 (Bad file descriptor). Retrying. --2018-01-25 18:15:46-- (try: 2) https://github-production-release-asset-2e65be.s3.amazonaws.com/41843105/f4… Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|54.231.115.35|:443... connected. HTTP request sent, awaiting response... 403 Forbidden 2018-01-25 18:15:47 ERROR 403: Forbidden. Also the download speed was super slow. Any ideas? Cheers, HernÃ¡n

Jan. 25, 2018

[ANN] Reed Solomon and Forward Error Correction

by henry

I spent time straightening out Foward Error Correction, using Reed Solomon encoding with Galois Fields. I mostly have it working for some algorithms, but still have an issue with AZTEC_DATA_10, and perhaps AZTEC_DATA_12. AZTEC_PARAM, AZTEC_DATA_6 and AZTEC_DATA_10 ar working, as well as DATA_MATRIX_FIELD_256 and QR_CODE_FIELD_256. I do not know if it is pluganizable, that would be super if code split into image and plugin, naturally. I have more testing to do to get those couple of algorithms working, then I will turn to QRCode and get that working. Thank you. Here is the code... http://www.squeaksource.com/Cryptography/fec-HenryHouse.7.mcz - HH

Jan. 25, 2018