test drive the peg grunt task functionality

tasks/peg.js

@@ -6,6 +6,8 @@
  * Licensed under the MIT license.
  */
 
+var PEG = require('pegjs');
+
 module.exports = function(grunt) {
 
   // Please see the grunt documentation for more information regarding task and
@@ -15,16 +17,21 @@ module.exports = function(grunt) {
   // TASKS
   // ==========================================================================
 
-  grunt.registerTask('peg', 'Your task description goes here.', function() {
-    grunt.log.write(grunt.helper('peg'));
+  grunt.registerMultiTask('peg', 'Generate a parser from a PEG grammar', function() {
+    grunt.log.write(grunt.template.process("Generating parser from <%= grammar %>", this.data));
+    var grammar = grunt.file.read(this.data.grammar);
+    grunt.file.write(this.data.outputFile, grunt.helper('peg', grammar, this.data.exportVar));
   });
 
   // ==========================================================================
   // HELPERS
   // ==========================================================================
 
-  grunt.registerHelper('peg', function() {
-    return 'peg!!!';
+  grunt.registerHelper('peg', function(grammar, exportVar) {
+    exportVar = exportVar || "module.exports";
+    var parser = PEG.buildParser(grammar);
+
+    return exportVar + " = " + parser.toSource() + ";";
   });
 
 };

test/peg_test.js

@@ -21,14 +21,13 @@ var grunt = require('grunt');
 */
 
 exports['peg'] = {
-  setUp: function(done) {
-    // setup here
-    done();
-  },
+  // setUp: function(done) {
+  //   grunt.file.write('test_data/a.js', grunt.helper('peg', "start = 'a'"));
+  //   done();
+  // },
   'helper': function(test) {
-    test.expect(1);
-    // tests here
-    test.equal(grunt.helper('peg'), 'peg!!!', 'should return the correct value.');
+    var expected = grunt.file.read('test_data/a.js')
+    test.equal(grunt.helper('peg', "start = 'a'"), expected, 'should return a proper grammar');
     test.done();
-  }
+  },
 };