June 2019 - Pharo-users - lists.pharo.org

Re: [Pharo-users] Find after in strings?

by Richard O'Keefe

To get #skipToAll: in Pharo, add this to PositionableStream. skipToAll: aCollection "Set the receiver's to just after the next occcurrence of aCollection in the receiver's future values and answer true. If there is no such On Sun, 2 Jun 2019 at 07:50, Tim Mackinnon <tim(a)testit.works> wrote: > Interesting - there is no #skipToAll: in pharo, I wonder why not? It > sounds like what I was looking for - and Iâm surprised its not there. There > is #skipTo: for an object (which sounds right, just not the string > equivalent). > > Iâm not doing anything special, just want to take some lines from the end > of a class comment and use them in an exercism exercise - but its not > different than many applications - find some tag and use the text after it. > Iâm kind of surprised its not in Pharo. > > Tim > > > On 1 Jun 2019, at 12:25, Richard O'Keefe <raoknz(a)gmail.com> wrote: > > If you want to move around in strings, you might want to use a ReadStream. > In some Smalltalk systems there is a method called #skipToAll:. > Here's how mine starts out: > > skipToAll: aSequence > "If the remaining elements can be parsed as <a><aSequence><b>, > return true leaving the position where? Otherwise return false. > > GNU Smalltalk, Dolphin, and VisualAge: > leave the position after <aSequence>, consistent with #upToAll:, > and implementable in this class. (GST uses the KMP algorithm.) > VisualWorks and ST/X: > leave the position before <aSequence>, inconsistent with > #upToAll:, > and only implementable for positionable streams. > Squeak 5.2 and Pharo 6.0: > not provided. > I cannot be compatible with everything. The semantics of > #skipToAll: should obviously match #upToAll:, so I'll fit > in with GNU, Dolphin, and VisualAge Smalltalk. > " > > So > (myReadStream skipToAll: 'marker') > ifTrue: [loc := myReadStream position] > ifFalse: [alternative code]. > > HOWEVER, I have a bad feeling about this. The entire approach, as with > much > concerning strings in a Unicode age, seems fraught with peril. Consider > input = 'the need for vigilance is never-ending' > marker = 'end' > Should the marker be found or not? > input = '.... Si<floating acute accent> ...' > marker = 'Si' > Should the marker be found or not? > My code is NOT sensitive to these issues. > I would like to say that it was because I was writing a compatibility > method, so my code was compatibly broken, > but to be honest, I was stupid and forgot to think it through. > I would think that there would need to be an '... asTokens: aBoolean' > variant that checks that a match > - is not followed by floating diacriticals > - is not preceded by an alphanumeric if the target begins with one > - is not followed by an alphanumeric if the target ends with one. > > My own preference is to write a lexical analyser for the mini-language > I'm using, and NOT try to hack at it using general-purpose string > methods. > > Perhaps you can tell us more about the context? What is the application- > level task you are trying to solve? > > > > On Sat, 1 Jun 2019 at 22:01, Tim Mackinnon <tim(a)testit.works> wrote: > >> Maybe this is a dumb question - and often Iâm surprised when asking >> these, but why is there no way to âfind afterâ a string. >> >> I find it rather boring to try and parse a string, after a known marker - >> thus: >> (loc := aString findString: âmarkerâ) > 0 ifTrue: [ loc := loc + âmarkerâ >> size ]. >> >> Is there a better way? This whole pattern seems very old and clunky and >> not smalltalk like? >> >> Couldnât we have: findAfter: aString ifAbsent: aBlock ? >> >> Or is there a whole better pattern for string searching that Iâm missing ? >> >> Tim >> > >

June 2, 2019

Re: [Pharo-users] Find after in strings?

by Tim Mackinnon

Classic - I went to implement #skipUpToAll: and its called #match: in Pharoâ¦. I struggle with some of the naming of string and stream methods in pharo/smalltalk and the protocols are often not quite what I expect either (altough in this case, match is âpositioningâ which is more in line with my thinking - but searching would be my first choice). Tim > On 1 Jun 2019, at 20:49, Tim Mackinnon <tim(a)testit.works> wrote: > > Interesting - there is no #skipToAll: in pharo, I wonder why not? It sounds like what I was looking for - and Iâm surprised its not there. There is #skipTo: for an object (which sounds right, just not the string equivalent). > > Iâm not doing anything special, just want to take some lines from the end of a class comment and use them in an exercism exercise - but its not different than many applications - find some tag and use the text after it. Iâm kind of surprised its not in Pharo. > > Tim > > >> On 1 Jun 2019, at 12:25, Richard O'Keefe <raoknz(a)gmail.com <mailto:raoknz@gmail.com>> wrote: >> >> If you want to move around in strings, you might want to use a ReadStream. >> In some Smalltalk systems there is a method called #skipToAll:. >> Here's how mine starts out: >> >> skipToAll: aSequence >> "If the remaining elements can be parsed as <a><aSequence><b>, >> return true leaving the position where? Otherwise return false. >> GNU Smalltalk, Dolphin, and VisualAge: >> leave the position after <aSequence>, consistent with #upToAll:, >> and implementable in this class. (GST uses the KMP algorithm.) >> VisualWorks and ST/X: >> leave the position before <aSequence>, inconsistent with #upToAll:, >> and only implementable for positionable streams. >> Squeak 5.2 and Pharo 6.0: >> not provided. >> I cannot be compatible with everything. The semantics of >> #skipToAll: should obviously match #upToAll:, so I'll fit >> in with GNU, Dolphin, and VisualAge Smalltalk. >> " >> >> So >> (myReadStream skipToAll: 'marker') >> ifTrue: [loc := myReadStream position] >> ifFalse: [alternative code]. >> >> HOWEVER, I have a bad feeling about this. The entire approach, as with much >> concerning strings in a Unicode age, seems fraught with peril. Consider >> input = 'the need for vigilance is never-ending' >> marker = 'end' >> Should the marker be found or not? >> input = '.... Si<floating acute accent> ...' >> marker = 'Si' >> Should the marker be found or not? >> My code is NOT sensitive to these issues. >> I would like to say that it was because I was writing a compatibility >> method, so my code was compatibly broken, >> but to be honest, I was stupid and forgot to think it through. >> I would think that there would need to be an '... asTokens: aBoolean' >> variant that checks that a match >> - is not followed by floating diacriticals >> - is not preceded by an alphanumeric if the target begins with one >> - is not followed by an alphanumeric if the target ends with one. >> >> My own preference is to write a lexical analyser for the mini-language >> I'm using, and NOT try to hack at it using general-purpose string >> methods. >> >> Perhaps you can tell us more about the context? What is the application- >> level task you are trying to solve? >> >> >> >> On Sat, 1 Jun 2019 at 22:01, Tim Mackinnon <tim(a)testit.works <mailto:tim@testit.works>> wrote: >> Maybe this is a dumb question - and often Iâm surprised when asking these, but why is there no way to âfind afterâ a string. >> >> I find it rather boring to try and parse a string, after a known marker - thus: >> (loc := aString findString: âmarkerâ) > 0 ifTrue: [ loc := loc + âmarkerâ size ]. >> >> Is there a better way? This whole pattern seems very old and clunky and not smalltalk like? >> >> Couldnât we have: findAfter: aString ifAbsent: aBlock ? >> >> Or is there a whole better pattern for string searching that Iâm missing ? >> >> Tim >

June 1, 2019

Re: [Pharo-users] Find after in strings?

by Tim Mackinnon

Interesting - there is no #skipToAll: in pharo, I wonder why not? It sounds like what I was looking for - and Iâm surprised its not there. There is #skipTo: for an object (which sounds right, just not the string equivalent). Iâm not doing anything special, just want to take some lines from the end of a class comment and use them in an exercism exercise - but its not different than many applications - find some tag and use the text after it. Iâm kind of surprised its not in Pharo. Tim > On 1 Jun 2019, at 12:25, Richard O'Keefe <raoknz(a)gmail.com> wrote: > > If you want to move around in strings, you might want to use a ReadStream. > In some Smalltalk systems there is a method called #skipToAll:. > Here's how mine starts out: > > skipToAll: aSequence > "If the remaining elements can be parsed as <a><aSequence><b>, > return true leaving the position where? Otherwise return false. > GNU Smalltalk, Dolphin, and VisualAge: > leave the position after <aSequence>, consistent with #upToAll:, > and implementable in this class. (GST uses the KMP algorithm.) > VisualWorks and ST/X: > leave the position before <aSequence>, inconsistent with #upToAll:, > and only implementable for positionable streams. > Squeak 5.2 and Pharo 6.0: > not provided. > I cannot be compatible with everything. The semantics of > #skipToAll: should obviously match #upToAll:, so I'll fit > in with GNU, Dolphin, and VisualAge Smalltalk. > " > > So > (myReadStream skipToAll: 'marker') > ifTrue: [loc := myReadStream position] > ifFalse: [alternative code]. > > HOWEVER, I have a bad feeling about this. The entire approach, as with much > concerning strings in a Unicode age, seems fraught with peril. Consider > input = 'the need for vigilance is never-ending' > marker = 'end' > Should the marker be found or not? > input = '.... Si<floating acute accent> ...' > marker = 'Si' > Should the marker be found or not? > My code is NOT sensitive to these issues. > I would like to say that it was because I was writing a compatibility > method, so my code was compatibly broken, > but to be honest, I was stupid and forgot to think it through. > I would think that there would need to be an '... asTokens: aBoolean' > variant that checks that a match > - is not followed by floating diacriticals > - is not preceded by an alphanumeric if the target begins with one > - is not followed by an alphanumeric if the target ends with one. > > My own preference is to write a lexical analyser for the mini-language > I'm using, and NOT try to hack at it using general-purpose string > methods. > > Perhaps you can tell us more about the context? What is the application- > level task you are trying to solve? > > > > On Sat, 1 Jun 2019 at 22:01, Tim Mackinnon <tim(a)testit.works> wrote: > Maybe this is a dumb question - and often Iâm surprised when asking these, but why is there no way to âfind afterâ a string. > > I find it rather boring to try and parse a string, after a known marker - thus: > (loc := aString findString: âmarkerâ) > 0 ifTrue: [ loc := loc + âmarkerâ size ]. > > Is there a better way? This whole pattern seems very old and clunky and not smalltalk like? > > Couldnât we have: findAfter: aString ifAbsent: aBlock ? > > Or is there a whole better pattern for string searching that Iâm missing ? > > Tim

June 1, 2019

Re: [Pharo-users] More Morphic snags

by Stephan Eggermont

Markus Stumptner <mst(a)cs.unisa.edu.au> wrote: > How do I reinstate that behaviour if a group is clicked on and the > double click does not happen? Neither document helps in explaining where > that "default" can be found in the code. Take a look at the code for the drag panels. I have some videos starting at https://vimeo.com/130781061 Iâm not sure the configurations are up to date for Pharo 7 Stephan

June 1, 2019

More Morphic snags

by Markus Stumptner

I have been trying to replicate the behaviour of an existing (non-Pharo, non-Smalltalk) application with Morphic. This provides grouping images in a workspace, and then switching between laying them out separately or "stacked" by double clicking on the group (or an image in it). When the group is stacked, it can be moved around as a single drag and drop operation. When the group is separated, dragging an image out of it removes it from the group. On the surface this looked like a perfect fit to the submorph tree.Â Unfortunately, as both the Morphic chapter in Pharo by Example and the intro document by Maloney make clear, if you enable double clicking (by answering true to #handlesMouseDown:), you are interfering with what Maloney calls the "default behaviour" of being able to drag a Morph around. How do I reinstate that behaviour if a group is clicked on and the double click does not happen? Neither document helps in explaining where that "default" can be found in the code. Thanks Markus

June 1, 2019

Re: [Pharo-users] Find after in strings?

by Richard O'Keefe

I forgot to mention that in order to be able to translate XPath to Smalltalk I added these methods to my Smalltalk: AbstractSequence>> afterSubCollection: aSequence [ifAbsent: exceptionBlock] "based on substring-after" beforeSubCollection: aSequence [ifAbsent: exceptionBlock] "based on substring-before" I'm not going to display the code, which is pretty simple, because there is a serious efficiency problem with these. (The Java equivalent, had there been one, would not have had this problem, but since I think Java 7 it would too.) Imagine that we have a string consisting of N instances of separators, and we want to split it into pieces. [s includesSubCollection: separator] whileTrue: [ self process: (s beforeSubCollection: separator). s := s afterSubCollection: separator]. s isEmpty ifFalse: [ self process: s]. Do I need to explain why this takes O(N**2) time? However, r := ReadStream on: s. [r atEnd] whileFalse: [ self process: (r upToAll: separator)]. is linear time (assuming an efficient #upToAll:). My previous remarks about boundary issues apply here as well, of course. My previous remarks about wanting to see the context do too. On Sun, 2 Jun 2019 at 00:43, Ben Coman <btc(a)openinworld.com> wrote: > On Sat, 1 Jun 2019 at 18:01, Tim Mackinnon <tim(a)testit.works> wrote: > > > > Maybe this is a dumb question - and often Iâm surprised when asking > these, but why is there no way to âfind afterâ a string. > > > > I find it rather boring to try and parse a string, after a known marker > - thus: > > (loc := aString findString: âmarkerâ) > 0 ifTrue: [ loc := loc + > âmarkerâ size ]. > > > > Is there a better way? This whole pattern seems very old and clunky and > not smalltalk like? > > > > Couldnât we have: findAfter: aString ifAbsent: aBlock ? > > > > Or is there a whole better pattern for string searching that Iâm missing > ? > > Can your input be split into tokens using Stirng>>findTokens: > and `ReadStream on: that`. Then you marker will be consumed by a single > #next. > > cheers -ben > >

June 1, 2019

Re: [Pharo-users] Find after in strings?

by Ben Coman

On Sat, 1 Jun 2019 at 18:01, Tim Mackinnon <tim(a)testit.works> wrote: > > Maybe this is a dumb question - and often Iâm surprised when asking these, but why is there no way to âfind afterâ a string. > > I find it rather boring to try and parse a string, after a known marker - thus: > (loc := aString findString: âmarkerâ) > 0 ifTrue: [ loc := loc + âmarkerâ size ]. > > Is there a better way? This whole pattern seems very old and clunky and not smalltalk like? > > Couldnât we have: findAfter: aString ifAbsent: aBlock ? > > Or is there a whole better pattern for string searching that Iâm missing ? Can your input be split into tokens using Stirng>>findTokens: and `ReadStream on: that`. Then you marker will be consumed by a single #next. cheers -ben

June 1, 2019

Re: [Pharo-users] Find after in strings?

by Richard O'Keefe

If you want to move around in strings, you might want to use a ReadStream. In some Smalltalk systems there is a method called #skipToAll:. Here's how mine starts out: skipToAll: aSequence "If the remaining elements can be parsed as <a><aSequence><b>, return true leaving the position where? Otherwise return false. GNU Smalltalk, Dolphin, and VisualAge: leave the position after <aSequence>, consistent with #upToAll:, and implementable in this class. (GST uses the KMP algorithm.) VisualWorks and ST/X: leave the position before <aSequence>, inconsistent with #upToAll:, and only implementable for positionable streams. Squeak 5.2 and Pharo 6.0: not provided. I cannot be compatible with everything. The semantics of #skipToAll: should obviously match #upToAll:, so I'll fit in with GNU, Dolphin, and VisualAge Smalltalk. " So (myReadStream skipToAll: 'marker') ifTrue: [loc := myReadStream position] ifFalse: [alternative code]. HOWEVER, I have a bad feeling about this. The entire approach, as with much concerning strings in a Unicode age, seems fraught with peril. Consider input = 'the need for vigilance is never-ending' marker = 'end' Should the marker be found or not? input = '.... Si<floating acute accent> ...' marker = 'Si' Should the marker be found or not? My code is NOT sensitive to these issues. I would like to say that it was because I was writing a compatibility method, so my code was compatibly broken, but to be honest, I was stupid and forgot to think it through. I would think that there would need to be an '... asTokens: aBoolean' variant that checks that a match - is not followed by floating diacriticals - is not preceded by an alphanumeric if the target begins with one - is not followed by an alphanumeric if the target ends with one. My own preference is to write a lexical analyser for the mini-language I'm using, and NOT try to hack at it using general-purpose string methods. Perhaps you can tell us more about the context? What is the application- level task you are trying to solve? On Sat, 1 Jun 2019 at 22:01, Tim Mackinnon <tim(a)testit.works> wrote: > Maybe this is a dumb question - and often Iâm surprised when asking these, > but why is there no way to âfind afterâ a string. > > I find it rather boring to try and parse a string, after a known marker - > thus: > (loc := aString findString: âmarkerâ) > 0 ifTrue: [ loc := loc + âmarkerâ > size ]. > > Is there a better way? This whole pattern seems very old and clunky and > not smalltalk like? > > Couldnât we have: findAfter: aString ifAbsent: aBlock ? > > Or is there a whole better pattern for string searching that Iâm missing ? > > Tim >

June 1, 2019