On 2012-12-29 1:47 PM, Levente Uzonyi wrote:
> On Sat, 29 Dec 2012, Chris Cunnington wrote:
>
>> I have a question about converting an OrderedCollection full of chars 
>> into a string. [1]
>
> | oc |
> oc := #($a $b $c) asOrderedCollection.
> oc as: String.
>
Thanks.
>>
>> I would have thought there was a method like #asString that could be 
>> sent to an OrderedCollection to produce a string. I find myself 
>> having to do the process in three steps: 1) #reading the OC; 2) 
>> creating an empty string; and then, 3) iterating over every char to 
>> put it into the String.
>
> Since the size of Strings (or an instance of a variable class in 
> general) can't be changed, therefore creating an empty String and 
> concatenating to it one character at a time is a bad pattern in 
> Smalltalk. Your algorithm will need O(n^2) time to finish (where n is 
> the number of characters), and you'll also waste O(n^2) space, which 
> will make your code even slower, since the intermediate collections 
> will have to be garbage collected.
>
>
> Levente
I rolled the versions forward and back to try them out. It's much slower 
concatenating one character at a time. I figured there had to be a 
better way, but wasn't seeing it.

Thanks,
Chris

>>
>> I think I'm missing a simpler way. Especially with Xtreams. Shouldn't 
>> I just use a filter, change the #contentSpecies, or something?
>>
>> Chris
>>
>>
>> [1]
>>
>> startTag: data
>>    <action: 'element'>
>>    |tagdata str |
>>    tagdata := data second first reading.
>>    str := (String new: 20) writing.
>>    tagdata do: [:each| str put: each].
>>    ^'html ' , (data first second first asString) , $: , $' , (str 
>> close; terminal) , $'
>>
>>
>>
>