From: naruse <naruse@...>
Date: 2012-03-18T15:05:15+09:00
Subject: [ruby-core:43392] [ruby-trunk - Feature #2645] Have a method in StringScanner which returns the position in characters rather than in bytes


Issue #2645 has been updated by naruse.

Description updated

gettalong wrote:
>  I had a similar problem: I wanted to extract a part of a StringScanner-backed string.
>  
>  Consider the following use case:
>  
>  * The StringScanner ss is used to arrive at a certain position.
>  * The current position is saved, ie. `start_pos = ss.pos`.
>  * Then ss is used to do some scanning, arriving at a new position: `end_pos = ss.pos`
>  * Extracting the string between start_pos and end_pos using `ss.string[start_pos..end_pos]` does not work in case the range contains multibyte characters.

You can use String#byteslice.
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Feature #2645: Have a method in StringScanner which returns the position in characters rather than in bytes
https://bugs.ruby-lang.org/issues/2645#change-24701

Author: stefanocr
Status: Feedback
Priority: Low
Assignee: 
Category: ext
Target version: 2.0.0


=begin
 In ruby 1.9, StringScanner#pos returns the position in number of bytes. I read on the ruby mailing list (http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/352809) this happens because working with character-based indexes would be too slow. However, I think it would be nice if StringScanner also provided a method which returned the position in terms of characters (even if it would be slow). As I see it, the situation is the same as with StringScanner#get_byte and StringScanner#getch. I think this would be useful because, when using StringScanner, you're usually interested in the character rather than in bytes.
=end



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