css: add isDocument, isText and isComment

src/css/libdom.zig

@@ -46,6 +46,21 @@ pub const Node = struct {
         return t == .element;
     }
 
+    pub fn isDocument(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .document;
+    }
+
+    pub fn isComment(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .comment;
+    }
+
+    pub fn isText(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .text;
+    }
+
     pub fn tag(n: Node) ![]const u8 {
         return try parser.nodeName(n.node);
     }

src/css/match_test.zig

@@ -36,6 +36,18 @@ pub const Node = struct {
         return true;
     }
 
+    pub fn isDocument(_: *const Node) bool {
+        return false;
+    }
+
+    pub fn isComment(_: *const Node) bool {
+        return false;
+    }
+
+    pub fn isText(_: *const Node) bool {
+        return false;
+    }
+
     pub fn tag(n: *const Node) ![]const u8 {
         return n.name;
     }

src/css/selector.zig

@@ -274,7 +274,7 @@ pub const Selector = union(enum) {
                         if (!try v.second.match(n)) return false;
                         var c = try n.prevSibling();
                         while (c != null) {
-                            if (!c.?.isElement()) { // TODO must check text node or comment node instead.
+                            if (c.?.isText() or c.?.isComment()) {
                                 c = try c.?.prevSibling();
                                 continue;
                             }
@@ -395,7 +395,7 @@ pub const Selector = union(enum) {
                         if (!n.isElement()) return false;
 
                         const p = try n.parent();
-                        return p == null;
+                        return (p != null and p.?.isDocument());
                     },
                     .link => {
                         const ntag = try n.tag();