Marko v3: Re-introduced <unless> tag support

taglibs/core/marko-taglib.json

@@ -27,6 +27,9 @@
         "code-generator": "./template-init-tag",
         "body": "static-text"
     },
+    "<unless>": {
+        "node-factory": "./unless-tag"
+    },
     "<var>": {
         "node-factory": "./var-tag"
     },

taglibs/core/unless-tag.js

@@ -0,0 +1,20 @@
+module.exports = function nodeFactory(elNode, context) {
+    var argument = elNode.argument;
+
+    if (!argument) {
+        context.addError(elNode, 'Invalid <unless> tag. Argument is missing. Example; <unless(foo === true)>');
+        return elNode;
+    }
+
+    var attributes = elNode.attributes;
+
+    if (attributes.length) {
+        context.addError(elNode, 'Invalid <unless> tag. Attributes not allowed.');
+        return;
+    }
+
+    var builder = context.builder;
+
+    var test = builder.parseExpression(argument);
+    return context.builder.ifStatement(builder.negate(test));
+};

test/fixtures/render/autotest/unless-else/template.marko

@@ -1,31 +1,31 @@
-<unless test="true">
+<unless(true)>
     A
 </unless>
 <else>
     B
 </else>
 ,
-<unless test="false">
+<unless(false)>
     A
 </unless>
 <else>
     B
 </else>
 ,
-<unless test="false">
+<unless(false)>
     A
 </unless>
-<else-if test="false">
+<else-if(false)>
     B
 </else-if>
 <else>
     C
 </else>
 ,
-<div unless="false">
+<div unless(false)>
     A
 </div>
-<div else-if="false">
+<div else-if(false)>
     B
 </div>
 <div else>