Re: parsing and string processing

Jeremy Kloth <[email protected]>
Newsgroups gmane.text.xml.expat.general
Organization Fourthought, Inc.
Message-ID <[email protected]>
On Thursday 27 October 2005 4:46 pm, Dave wrote:
> I looked at the source code but couldn't understand
> exactly what getAtts and scanAtts do. What I'm trying
> to find out is if they do any sort of string/pattern
> matching.

For the most part, they do *character* matching.  The XML specification 
defines the sets of characters that are allowed at any given point in a XML 
document.

> Or maybe a general question, do xml parsers 
> do string/pattern matching a lot?

Some parsers are implemented by using regular expressions (is that what you 
mean by "string/pattern matching"?).  Expat does basically the same thing, 
just unrolled in very optimized sub-functions for the respective 
non-terminals defined in the specification.

> If yes, how much does it affect performance?

It is basically a fact of life for any tokenizing lexer, be it a compiler, a 
XML parser, regular expression engine and what-not, the list is quite endless 
in the programming world.

> Thank you for your help! 

No problem, however I am curious as to the fascination with "string/pattern 
matching" as I seen basically this same message on the xml-sig list.

-- 
Jeremy Kloth
Fourthought, Inc.
http://fourthought.com/
http://4suite.org/
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