public bool parse(string text)
{
if (string.IsNullOrEmpty(text))
{
return(false);
}
var tokens = new List <string>();
html.split_string(text, tokens, "", " \t>+~", "([");
if (tokens.Count == 0)
{
return(false);
}
var right = tokens[tokens.Count - 1].Trim();
var combinator = '\0';
tokens.RemoveAt(tokens.Count - 1);
string lastToken;
while (tokens.Count != 0 && ((lastToken = tokens[tokens.Count - 1]) == " " || lastToken == "\t" || lastToken == "+" || lastToken == "~" || lastToken == ">"))
{
if (combinator == ' ' || combinator == 0)
{
combinator = lastToken[0];
}
tokens.RemoveAt(tokens.Count - 1);
}
var left = tokens.Aggregate(new StringBuilder(), (a, b) => a.Append(b)).ToString().Trim();
if (string.IsNullOrEmpty(right))
{
return(false);
}
_right.parse(right);
switch (combinator)
{
case '>': _combinator = css_combinator.child; break;
case '+': _combinator = css_combinator.adjacent_sibling; break;
case '~': _combinator = css_combinator.general_sibling; break;
default: _combinator = css_combinator.descendant; break;
}
_left = null;
if (!string.IsNullOrEmpty(left))
{
_left = new css_selector((media_query_list)null);
if (!_left.parse(left))
{
return(false);
}
}
return(true);
}
public void CssSelectorParseTest()
{
var selector = new css_selector();
// https://www.w3schools.com/cssref/css_selectors.asp
Assert.IsFalse(selector.parse(string.Empty));
Assert.IsTrue(selector.parse("element")); Assert.AreEqual(selector._combinator, css_combinator.descendant); Assert.AreEqual(selector._right._tag, "element"); Assert.AreEqual(selector._right._attrs.Count, 0); Assert.IsNull(selector._left);
//Assert.IsTrue(selector.parse("element,element")); Assert.AreEqual(selector._combinator, css_combinator.descendant); Assert.AreEqual(selector._right._tag, "element"); Assert.AreEqual(selector._right._attrs.Count, 0);
Assert.IsTrue(selector.parse(".class1 .class2")); Assert.AreEqual(selector._combinator, css_combinator.descendant); Assert.IsEmpty(selector._right._tag); Assert.AreEqual(selector._right._attrs.Count, 1); Assert.AreEqual(selector._left._right._attrs.Count, 1);
Assert.IsTrue(selector.parse("element element")); Assert.AreEqual(selector._combinator, css_combinator.descendant); Assert.AreEqual(selector._right._tag, "element"); Assert.AreEqual(selector._right._attrs.Count, 0); Assert.AreEqual(selector._left._right._tag, "element");
Assert.IsTrue(selector.parse("element>element")); Assert.AreEqual(selector._combinator, css_combinator.child); Assert.AreEqual(selector._right._tag, "element"); Assert.AreEqual(selector._right._attrs.Count, 0); Assert.AreEqual(selector._left._right._tag, "element");
Assert.IsTrue(selector.parse("element+element")); Assert.AreEqual(selector._combinator, css_combinator.adjacent_sibling); Assert.AreEqual(selector._right._tag, "element"); Assert.AreEqual(selector._right._attrs.Count, 0); Assert.AreEqual(selector._left._right._tag, "element");
Assert.IsTrue(selector.parse("element1~element2")); Assert.AreEqual(selector._combinator, css_combinator.general_sibling); Assert.AreEqual(selector._right._tag, "element2"); Assert.AreEqual(selector._right._attrs.Count, 0); Assert.AreEqual(selector._left._right._tag, "element1");
}
bool parse_selectors(string txt, style styles, media_query_list media)
{
var tokens = new List <string>();
html.split_string(txt.Trim(), tokens, ",");
var added_something = false;
foreach (var tok in tokens)
{
var selector = new css_selector(media);
selector._style = styles;
if (selector.parse(tok.Trim()))
{
selector.calc_specificity();
add_selector(selector);
added_something = true;
}
}
return(added_something);
}