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Ticket #59 (assigned enhancement)

Last modified 17 months ago

Support XPaths with predicate expressions

Reported by:	ecmanaut	Owned by:	why
Priority:	major	Milestone:
Component:	ext/hpricot_scan	Version:
Keywords:		Cc:

Description

When singling out nodes, it is often useful to be able to point at some node along the path, using a basic transform along the lines of this. The latter two expressions are different ways of phrasing the same thing, but the shorter version does not work:

doc.search('//tr/td/a[@href^="diary_read"]').length # => 20 (is correct)
doc.search('//tr[td/a[@href^="diary_read"]]').length # => 561 (want 20!)
doc.search('//tr/td/a[@href^="diary_read"]/../..').length # => 20 (okay)

I'd love to have all three render the same amount of nodes so I won't have to translate my XPath thoughts into HpricotPath? quite so often. There wouldn't happen to be any chances of metaprogramming up something cool that would let a real XPath engine explore Hpricot's inner state to run queries against it, using W3C style XPath, barfing on everything else?

Change History

in reply to: ↑ 1 Changed 20 months ago by ecmanaut

Replying to why:

I find it insane (for once, in the bad way) to support two different incompatible syntaxes in the same method, without a way of marking which syntax was used. Support for both CSS and XPath is great, but I would prefer separate method signatures for each syntax. Ideally, css() and xpath() (perhaps prefixed "by_" or similar), rather than the common search(), which could be left to rot slowly as backwards compat with its flaws and issues.

Regarding the "/" shorthand, I'd vote for making it handle either of the two, and suggest picking CSS, since Hpricot's CSS support for it seems much closer to full coverage than its XPath syntax, and since more people are familiar with CSS.

Changed 17 months ago by badyacorp

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