protected override IEnumerable <LessNode> EvaluateCore(EvaluationContext context)
{
if (Guard?.SatisfiedBy(context) == false)
{
yield break;
}
var evaluatedSelectors = Selectors.Inherit(context.CurrentScope.Selectors).EvaluateSingle <SelectorList>(context);
evaluatedSelectors.AddExtenders(context);
using (context.EnterScope(evaluatedSelectors)) {
(var rules, var others) = Block.Evaluate(context).Split <Rule, Statement>();
if (rules.Count > 0)
{
var ruleLookup = new HashSet <Rule>();
for (var i = rules.Count - 1; i >= 0; i--)
{
var r = rules[i];
if (ruleLookup.Contains(r))
{
rules.RemoveAt(i);
}
else
{
ruleLookup.Add(r);
}
}
var evaluatedBlock = new RuleBlock(rules);
var evaluatedRuleset =
new Ruleset(evaluatedSelectors, evaluatedBlock);
yield return(evaluatedRuleset);
}
foreach (var statement in others)
{
if (statement is Ruleset rs)
{
context.CurrentScope.Parent.DeclareRuleset(rs);
yield return(rs);
}
else if (statement is MediaBlock media)
{
yield return(media.Bubble(context));
}
else if (statement is Stylesheet || statement is ImportStatement)
{
yield return(statement);
}
else
{
throw new EvaluationException($"Unexpected statement type after evaluating rule block: {statement.GetType()}");
}
}
}
}
