Bug 704832 (echoxml): Clarify comments, which includes

extracting unclosedJs variable which slightly helps code clarity
but also helps comment clarity

lib/gcli/ui/inputter.js

@@ -551,14 +551,17 @@ Completer.prototype.update = function(input) {
 
   dom.clearElement(this.element);
 
-  // All this DOM manipulation is equivalent to the following template. It's
-  // not in a template because appendMarkupStatus() needs to merge spans.
+  // All this DOM manipulation is equivalent to the HTML below.
+  // It's not a template because it's very simple except appendMarkupStatus()
+  // which is complex due to a need to merge spans.
   // Bug 707131 questions if we couldn't simplify this to use a template.
   //
   // <span class="gcli-prompt">${completionPrompt}</span>
   // ${appendMarkupStatus()}
   // ${prefix}
-  // <span class="gcli-in-ontab">${suffixSpanContents}</span>
+  // <span class="gcli-in-ontab">${contents}</span>
+  // <span class="gcli-in-closebrace" if="${unclosedJs}">}<span>
+
   var document = this.element.ownerDocument;
   var prompt = document.createElement('span');
   prompt.classList.add('gcli-prompt');
@@ -584,8 +587,8 @@ Completer.prototype.update = function(input) {
       contents = tab.slice(existing.length - numLeadingSpaces);
     } else {
       // Display the '-> prediction' at the end of the completer element
-      prefix = ' \u00a0';
-      contents = '\u21E5 ' + tab;
+      prefix = ' \u00a0';         // aka &nbsp;
+      contents = '\u21E5 ' + tab; // aka &rarr; the right arrow
     }
 
     if (prefix != null) {
@@ -598,16 +601,16 @@ Completer.prototype.update = function(input) {
     this.element.appendChild(suffix);
   }
 
-  // A hack to add a grey '}' to the end of the command line when we've opened
+  // Add a grey '}' to the end of the command line when we've opened
   // with a { but haven't closed it
   var command = this.requisition.commandAssignment.getValue();
-  if (command && command.name === '{') {
-    if (this.requisition.getAssignment(0).getArg().suffix.indexOf('}') === -1) {
-      var close = document.createElement('span');
-      close.classList.add('gcli-in-closebrace');
-      close.appendChild(document.createTextNode('}'));
-      this.element.appendChild(close);
-    }
+  var unclosedJs = command && command.name === '{' &&
+          this.requisition.getAssignment(0).getArg().suffix.indexOf('}') === -1;
+  if (unclosedJs) {
+    var close = document.createElement('span');
+    close.classList.add('gcli-in-closebrace');
+    close.appendChild(document.createTextNode('}'));
+    this.element.appendChild(close);
   }
 };