[Python-Dev] The "lazy strings" patch [was: PATCH submitted: Speed up + for string concatenation, now as fast as "".join(x) idiom]

[Larry Hastings]

On 2006/10/20, Larry Hastings wrote:
> I'm ready to post the patch.
Sheesh!  Where does the time go.


I've finally found the time to re-validate and post the patch.  It's 
SF.net patch #1590352:
    
http://sourceforge.net/tracker/index.php?func=detail&aid=1590352&group_id=5470&atid=305470
I've attached both the patch itself (against the current 2.6 revision, 
52618) and a lengthy treatise on the patch and its ramifications as I 
understand them.

I've also added one more experimental change: a new string method, 
str.simplify().  All it does is force a lazy concatenation / lazy slice 
to render.  (If the string isn't a lazy string, or it's already been 
rendered, str.simplify() is a no-op.)  The idea is, if you know these 
consarned "lazy slices" are giving you the oft-cited horrible memory 
usage scenario, you can tune your app by forcing the slices to render 
and drop their references.  99% of the time you don't care, and you 
enjoy the minor speedup.  The other 1% of the time, you call .simplify() 
and your code behaves as it did under 2.5.  Is this the right approach?  
I dunno.  So far I like it better than the alternatives.  But I'm open 
to suggestions, on this or any other aspect of the patch.

Cheers,


/larry/