Ok, thanks so much for the help. I went with DOM-parsing to begin with, I'll explore XPath + SimpleXML later. Thanks, Waynn On Mon, May 12, 2008 at 5:23 AM, David Otton <phpmail@xxxxxxxxxxxxxxxxxxxxxxx> wrote: > 2008/5/12 Waynn Lue <waynnlue@xxxxxxxxx>: >> So if I'm looking to parse certain attributes out of an XML tree, if I >> use SAX, it seems that I would need to keep track of state internally. >> E.g., if I have a tree like >> >> <head> >> <a> >> <b></b> >> </a> >> <a> >> <b></b> >> </a> >> </head> >> >> and say I'm interested in all that's between <b> underneath any <a>, >> I'd need to have a state machine that looked for an <a> followed by a >> <b>. If I'm doing that, though, it seems like I should just start >> using a DOM parser instead? > > Yeah, I think you've got it nailed, although your example is simple > enough (you're only holding one state value - "am I a child of <a>?") > that I'd probably still reflexively reach for the lightweight > solution). I use SAX for lightweight hacks, one step up from regexes - > I know the information I want is between <tag> and </tag>, and I don't > care about the rest of the document. The more I need to navigate the > document, the more likely I am to use DOM. I could build my own data > structures on top of a SAX parser, but why bother reinventing the > wheel? Of course, you have to factor document size into that - parsing > a big XML document into a tree can be slow. > > You might also want to explore XPath > (http://uk.php.net/manual/en/function.simplexml-element-xpath.php > http://uk.php.net/manual/en/class.domxpath.php)... XPath is to XML as > Regexes are to text files. There's a good chance you'll be able to > roll all your parsing up into a couple of XPath queries. > > I probably should have added that simple parsers come in two flavours > - Push Parsers and Pull Parsers. I tend to think (lazily) of Push and > Pull as variations on SAX, but strictly speaking they are different. > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
