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@testit.works> wrote:
> 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 <rao...@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@testit.works> 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
>>
>
>
