implement :first-child

Author: lloyd

src/jsonselect.js

@@ -131,12 +131,16 @@
         return to;
     }
 
-    function mn(node, sel, id) {
+    function mn(node, sel, id, num) {
         var sels = [];
         var cs = (sel[0] === '>') ? sel[1] : sel[0];
         var m = true;
         if (cs.type) m = m && (cs.type === mytypeof(node));
         if (cs.id)   m = m && (cs.id === id);
+        if (m && cs.pc) {
+            if (cs.pc === ":first-child") m = (num === 0);
+            else if (cs.pc === ":last-child") m = m; // XXX
+        }
 
         // should we repeat this selector for descendants?
         if (sel[0] !== '>' && sel[0].pc !== ":root") sels.push(sel);
@@ -150,21 +154,22 @@
         return [m, sels];
     }
 
-    function forEach(sel, obj, fun, id) {
+    function forEach(sel, obj, fun, id, num) {
         var a = (sel[0] === ',') ? sel.slice(1) : [sel];
         var a0 = [];
         var call = false;
         for (var i = 0; i < a.length; i++) {
-            var x = mn(obj, a[i], id);
+            var x = mn(obj, a[i], id, num);
             if (x[0]) call = true;
             for (var j = 0; j < x[1].length; j++) a0.push(x[1][j]);
         }
         if (a0.length && typeof obj === 'object') {
             if (a0.length >= 1) a0.unshift(",");
             if (isArray(obj)) {
-                for (var i = 0; i < obj.length; i++) forEach(a0, obj[i], fun);
+                for (var i = 0; i < obj.length; i++) forEach(a0, obj[i], fun, undefined, i);
             } else {
-                for (var k in obj) if (obj.hasOwnProperty(k)) forEach(a0, obj[k], fun, k);
+                var i = 0;
+                for (var k in obj) if (obj.hasOwnProperty(k)) forEach(a0, obj[k], fun, k, i++);
             }
         }
         if (call && fun) fun(obj);