Hi ! This PR adds support for specificity of CSS selectors.

The package API doesn't change; one method is added on the top-level Selector type.

Internally, one type oneSelector is added, which wraps a matching function and a specificity. The new Selector type becomes a list of oneSelector, to support comma-separated groups of selectors.

I added a few tests for specificity; all older tests passe.

Hi again, This PR adds support for pseudo elements.

The approach taken boils down to adding a method PseudoElement on Sel, even for simple selectors, where the implementation is "empty".

../../go/src/github.com/andybalholm/cascadia/parser.go:11:2: cannot find package "golang.org/x/net/html"

Need to update to https://github.com/golang/net ?

• [*] use html.Render() to replace nodeString(). Closed #23.
• [+] add two more multiple attribute selector test cases

You may want to take a closer look at the following code,

	{
		`<ul>
			<li><a id="a1" href="http://www.google.com/finance"></a>
			<li><a id="a2" href="http://finance.yahoo.com/"></a>
			<li><a id="a2" href="http://finance.untrusted.com/"/>
			<li><a id="a3" href="https://www.google.com/news"/>
			<li><a id="a4" href="http://news.yahoo.com"/>
		</ul>`,
		`[href#=(fina)]:not([href#=(\/\/[^\/]+untrusted)])`,
		[]string{
			`<a id="a1" href="http://www.google.com/finance"></a>`,
			`<a id="a2" href="http://finance.yahoo.com/"></a>`,
		},

and make some changes, and of course you may leave it as-is as well.

It would be nice to add a case-insensitive attribute search. Now this is possible only through regex which has a low performance. Instead it possible to add the css 4 syntax (https://css4-selectors.com/selector/css4/attribute-case-sensitivity/). Under the hood you can use the EqualFold Go function for checking equality which has much better performance against Regex

For example, this tags

<div class="Red">
<div class="red">

can be find by div[class="red" i] selector

It looks like this is the offending line:

https://github.com/andybalholm/cascadia/blob/master/parser.go#L101

Simple test case:

func TestDoubleDash(t *testing.T) {
	// Works
	_, err := cascadia.Compile(".-foobar")
	if err != nil {
		t.Error("Should succeed with single dash")
	}

	// Doesn't work
	_, err = cascadia.Compile(".--foobar")
	if err != nil {
		t.Error("Should succeed with double dash")
	}
}

Hi Andy,

I'm wondering what your considerations were when choosing to use nodeString() function (instead of html.Render()) in your selector_test.go file. I mean, html.Render() would work as well, right?

The reason I'm asking is that, I think people would be more interested in the actual effect on html.Render(). Thx.

I'm using goquery, and retrieved a selection. I want to do a further query on that selection, requiring direct descendents of the selected nodes, so I start my query with '>'. For example say I find a particular 'ul' element, then want to target direct child 'li' elements in a later query on the selection containing the 'ul', I'd pass '> li'. Perhaps I'm not doing this right, but it seems jQuery supports it, but cascadia will not. Thanks.

https://github.com/PuerkitoBio/goquery/issues/117

Similar to that problem: http://stackoverflow.com/questions/5552462/handling-colon-in-element-id-with-jquery

Double backslashes doesn't work

<div id="test:abc" value="123">

value, exists := doc.Find("div#test:abc").Attr("value")
  if exists == false {
          log.Fatal("Not found\n")
  } else {
  log.Printf("Value: %s\n", value)

panic: unknown pseudoclass :abc

goroutine 1 [running]:
github.com/andybalholm/cascadia.MustCompile(0x7f1020, 0x23, 0xc82006a380)
        /go/src/github.com/andybalholm/cascadia/selector.go:59 +0x72
github.com/PuerkitoBio/goquery.(*Selection).Find(0xc8201887b0, 0x7f1020, 0x23, 0x0)
        /go/src/github.com/PuerkitoBio/goquery/traversal.go:27 +0x38
main.ExampleScrape()
        /go/src/test/test.go:16 +0x7e
main.main()
        /go/src/test/test.go:42 +0x14

This adds :input selector that matches input, select, textarea and button elements like Sizzle (https://github.com/jquery/sizzle/blob/a6ca3e9919c7a77001bdec01b3579e4bafd73a84/src/sizzle.js#L129)

@andybalholm are you okay with this?

Hi,

my project is using this one as a lib. After some slight changes on webpage that it parsers there is a panic: https://github.com/Komosa/cf/issues/4

I suppose there is just a need to handle it around lines from stacktrace. But filling an issue for reference. offending line: gopath.../github.com/andybalholm/cascadia/selector.go:217

Problem

Cascadia seems to fail with the has psudo-class and a direct child selector

From MDN

The following selector matches only elements that directly contain an child: a:has(> img)

var selectorTests = []selectorTest{
	{
		`<html><a><img></img></a></html>`,
		"a:has(> img)",
		[]string{
			"<a><img></img></a>",
		},
	},
        ...
}