handle empty strings in compiler.

example/tput.js

@@ -2,7 +2,7 @@ var Tput = require('../').Tput;
 
 var tput = Tput({
   term: process.argv[2] || 'xterm',
-  extended: false,
+  extended: !!~process.argv.indexOf('--extended'),
   debug: true
 });
 

lib/tput.js

@@ -452,6 +452,10 @@ Tput.prototype._compile = function(val) {
       return function() {};
   }
 
+  //if (!val) {
+  //  return noop;
+  //}
+
   var code = 'var v, dyn = {}, stat = {}, stack = [], out = [];'
     , buff = ''
     , cap;
@@ -837,6 +841,7 @@ Tput.prototype._compile = function(val) {
 
   stmt(';return out.join("");');
 
+  // TODO: Make this less ridiculous.
   // Optimize
   //  ... out.push("foo");return out.join("");
   // To:
@@ -844,6 +849,8 @@ Tput.prototype._compile = function(val) {
   v = code.split(/out = \[\];out\.push\(|\);return out/);
   if (v.length === 3 && /^"[^"]+"$/.test(v[1])) {
     code = 'return ' + v[1] + ';';
+  } else if (~code.indexOf('out = [];;return')) {
+    code = 'return "";';
   }
 
   if (this.debug) {