From: Lothar Scholz <mailinglists@...>
Date: 2005-06-05T06:04:02+09:00
Subject: Re: Question about string's in-place modification

Hello Sam,

SK> Hello!

SK> I wonder how destructive methods work in the behind.

SK> For example,

SK> s = '12345'
SK> s2 = s
SK> s.sub!('3', 'three')
puts s #->>'12three45'
puts s2 #->>'12three45'

SK> Destructive methods are in-place.
SK> Does that mean the object doesn't change its location in memory?
SK> Probably not.
SK> I don't think it's possible as the object might need more space and
SK> need to move to a bigger empty space for the changed data.
SK> If it moves, the references pointing to it should be updated as well.

SK> How exactly does that work?

A string is of c type VALUE (as every ruby object). This c type hold
at least 16 byte. So there is enough space to keep a string length and
the pointer inside the object.


SK> Thanks in advance.
SK> Sam




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 Lothar Scholz                        http://www.ruby-ide.com
 CTO Scriptolutions                   Ruby, PHP, Python IDE 's