added caching to require extension

lib/tamejs.js

@@ -2,16 +2,44 @@
 "use strict";
 
 var runtime = require ('./runtime').runtime;
+var fs = require('fs');
+var path = require('path');
+var engineVersion = "0.4.3";
+
 exports.runtime = runtime;
 
 //-----------------------------------------------------------------------
 
 function _extension (module, filename) {
-    var Engine = require ('./engine').Engine;
-    var engine = new Engine (filename);
-    engine.readInputSync ();
-    engine.parse ();
-    var out = engine.compile ().formatOutput ();
+
+    var cachePath = path.join(path.dirname(filename), "." + path.basename(filename) + "." + engineVersion + ".cache");
+
+    try{
+        var cacheStats = fs.statSync(cachePath);
+    }catch(e){ cacheStats = null; }
+
+    var recompile = true;
+    if(cacheStats){
+        var tjsStats = fs.statSync(filename);
+
+        if(cacheStats.mtime >  tjsStats.mtime){ 
+            recompile = false;
+        }
+    }
+
+    var out = "";
+
+    if(recompile){
+        var Engine = require ('./engine').Engine;
+        var engine = new Engine (filename);
+        engine.readInputSync ();
+        engine.parse ();
+        out = engine.compile ().formatOutput ();
+        fs.writeFile(cachePath, out);
+    }else{
+        out = fs.readFileSync(cachePath, 'utf8');
+    }
+
     module._compile (out, filename);
 };
 
@@ -31,14 +59,14 @@ function register (options) {
 
     if (!options) { options = {}; }
     else if (typeof (options) == 'string' || options instanceof Array) { 
-	options = { extension : options } ;
+    	options = { extension : options } ;
     }
 
     var ext = "tjs";
     if (options.extension) { ext = options.extension; }
     if (!(ext instanceof Array)) { ext = [ ext ]; }
     for (var e in ext) {
-	require.extensions["." + ext[e]] = _extension;
+	    require.extensions["." + ext[e]] = _extension;
     }
 
     if (options.catchExceptions) { runtime.catchExceptions (); }