Interesting - there is no #skipToAll: in pharo, I wonder why not? It sounds like what I was looking for - and I’m surprised its not there. There is #skipTo: for an object (which sounds right, just not the string equivalent).
I’m 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. I”m kind of surprised its not in Pharo. Tim > On 1 Jun 2019, at 12:25, Richard O'Keefe <[email protected]> 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 <[email protected]> wrote: > Maybe this is a dumb question - and often I’m surprised when asking these, > but why is there no way to “find after” a string. > > I find it rather boring to try and parse a string, after a known marker - > thus: > (loc := aString findString: ‘marker’) > 0 ifTrue: [ loc := loc + ‘marker’ > size ]. > > Is there a better way? This whole pattern seems very old and clunky and not > smalltalk like? > > Couldn’t we have: findAfter: aString ifAbsent: aBlock ? > > Or is there a whole better pattern for string searching that I’m missing ? > > Tim
