adding upon

Author: heydariplusplus

src/Parser.js

@@ -23,7 +23,7 @@
  *     <block>         :== ( <comment> | <command> | <control> | <function> |
  *                           <statement> )[0..n]
  *
- *     <control>       :== <if> | <for> | <while> | <repeat>
+ *     <control>       :== <if> | <for> | <while> | <repeat> | <upon>
  *     <if>            :== \IF{<cond>} <block>
  *                         ( \ELIF{<cond>} <block> )[0..n]
  *                         ( \ELSE <block> )[0..1]
@@ -32,6 +32,7 @@
  *     <for>           :== \FOR{<cond>} <block> \ENDFOR
  *     <while>         :== \WHILE{<cond>} <block> \ENDWHILE
  *     <repeat>        :== \REPEAT <block> \UNTIL{<cond>}
+ *     <upon>          :== \UPON{<cond>} <block> \EDNUPON
  *
  *     <function>      :== \FUNCTION{<name>}{<params>} <block> \ENDFUNCTION
  *                         (same for <procedure>)
@@ -261,6 +262,7 @@ Parser.prototype._parseControl = function() {
     if ((controlNode = this._parseIf())) return controlNode;
     if ((controlNode = this._parseLoop())) return controlNode;
     if ((controlNode = this._parseRepeat())) return controlNode;
+    if ((controlNode = this._parseUpon())) return controlNode;
 };
 
 Parser.prototype._parseFunction = function() {
@@ -361,6 +363,23 @@ Parser.prototype._parseRepeat = function() {
     return repeatNode;
 };
 
+Parser.prototype._parseUpon = function() {
+    if (!this._lexer.accept('func', 'upon')) return null;
+
+    var uponNode = new ParseNode('upon');
+
+    // { <cond> } <block>
+    this._lexer.expect('open');
+    uponNode.addChild(this._parseCond());
+    this._lexer.expect('close');
+    uponNode.addChild(this._parseBlock());
+
+    // \ENDUPON
+    this._lexer.expect('func', 'endupon');
+
+    return uponNode;
+};
+
 var IO_STATEMENTS = ['ensure', 'require', 'input', 'output'];
 var STATEMENTS = ['state', 'print', 'return'];
 Parser.prototype._parseStatement = function(acceptStatements) {

src/Renderer.js

@@ -785,7 +785,7 @@ Renderer.prototype._buildTree = function(node) {
             this._buildCommentsFromBlock(repeatBlock);
             this._buildTree(repeatBlock);
 
-            
+
             // \UNTIL{<cond>}
             // ==>
             // <p class="ps-line">
@@ -795,7 +795,28 @@ Renderer.prototype._buildTree = function(node) {
             this._typeKeyword('until ');
             var repeatCond = node.children[1];
             this._buildTree(repeatCond);
-            
+
+            break;
+        case 'upon':
+            // \UPON { <cond> }
+            // ==>
+            // <p class="ps-line">
+            //      <span class="ps-keyword">upon</span>
+            // </p>
+            this._newLine();
+            this._typeKeyword('upon ');
+            uponCond = node.children[0];
+            this._buildTree(uponCond);
+            // <block>
+            var uponBlock = node.children[1];
+            this._buildCommentsFromBlock(uponBlock);
+            this._buildTree(uponBlock);
+
+            if (!this._options.noEnd) {
+                // ENDUPON
+                this._newLine();
+                this._typeKeyword('end upon');
+            }
             break;
         // ------------------- Lines -------------------
         case 'command':