diff --git a/gulpfile.js b/gulpfile.js
index 806c284..277ff9f 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -8,51 +8,29 @@ let eslint = require("gulp-eslint");
 let gulp = require("gulp");
 let header = require("gulp-header");
 let mocha = require("gulp-mocha");
-let package_ = require("./package");
-let peg = require("./lib/peg");
 let rename = require("gulp-rename");
 let runSequence = require("run-sequence");
 let source = require("vinyl-source-stream");
 let spawn = require("child_process").spawn;
-let transform = require("gulp-transform");
 let uglify = require("gulp-uglify");
 
-const HEADER = [
-  "// PEG.js " + package_.version,
-  "//",
-  "// https://pegjs.org/",
-  "//",
-  "// Copyright (c) 2010-2016 David Majda",
-  "// Licensed under the MIT License.",
-  ""
-].map(line => `${line}\n`).join("");
-
-const JS_FILES = [
-  "lib/**/*.js",
-  "!lib/parser.js",
-  "test/benchmark/**/*.js",
-  "test/benchmark/run",
-  "test/impact",
-  "test/spec/**/*.js",
-  "test/server/run",
-  "bin/*.js",
-  "gulpfile.js"
-];
-
-const TEST_FILES = [
-  "test/spec/**/*.js"
-];
-
-function generate(contents) {
-  return peg.generate(contents.toString(), {
-    output: "source",
-    format: "commonjs"
-  });
+function execFile(args) {
+  return spawn("node", args.split(" "), { stdio: "inherit" });
 }
 
 // Run ESLint on all JavaScript files.
 gulp.task("lint", () =>
-  gulp.src(JS_FILES)
+  gulp.src([
+    "lib/**/*.js",
+    "!lib/parser.js",
+    "test/benchmark/**/*.js",
+    "test/benchmark/run",
+    "test/impact",
+    "test/spec/**/*.js",
+    "test/server/run",
+    "bin/*.js",
+    "gulpfile.js"
+  ])
     .pipe(eslint())
     .pipe(eslint.format())
     .pipe(eslint.failAfterError())
@@ -60,18 +38,31 @@ gulp.task("lint", () =>
 
 // Run tests.
 gulp.task("test", () =>
-  gulp.src(TEST_FILES, { read: false })
+  gulp.src("test/spec/**/*.spec.js", { read: false })
     .pipe(mocha())
 );
 
 // Run benchmarks.
-gulp.task("benchmark", () =>
-  spawn("node", ["test/benchmark/run"], { stdio: "inherit" })
-);
+gulp.task("benchmark", () => execFile("test/benchmark/run"));
 
 // Create the browser build.
-gulp.task("browser:build", () =>
-  browserify("lib/peg.js", { standalone: "peg" })
+gulp.task("browser:build", () => {
+  const HEADER = [
+    "//",
+    "// PEG.js v" + require("./package").version,
+    "// https://pegjs.org/",
+    "//",
+    "// Copyright (c) 2010-2016 David Majda",
+    "// Copyright (c) 2017+ Futago-za Ryuu",
+    "//",
+    "// Licensed under the MIT License.",
+    "//",
+    ""
+  ]
+    .map(line => `${line}\n`)
+    .join("");
+
+  return browserify("lib/peg.js", { standalone: "peg" })
     .transform(babelify, { presets: "es2015", compact: false })
     .bundle()
     .pipe(source("peg.js"))
@@ -81,20 +72,15 @@ gulp.task("browser:build", () =>
     .pipe(buffer())
     .pipe(uglify())
     .pipe(header(HEADER))
-    .pipe(gulp.dest("browser"))
-);
+    .pipe(gulp.dest("browser"));
+});
 
 // Delete the browser build.
-gulp.task("browser:clean", () =>
-  del("browser")
-);
+gulp.task("browser:clean", () => del("browser"));
 
 // Generate the grammar parser.
 gulp.task("parser", () =>
-  gulp.src("src/parser.pegjs")
-    .pipe(transform(generate))
-    .pipe(rename({ extname: ".js" }))
-    .pipe(gulp.dest("lib"))
+  execFile("bin/peg src/parser.pegjs -o lib/parser.js")
 );
 
 // Default task.
diff --git a/package.json b/package.json
index d90ab4f..bedc0e3 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,6 @@
     "gulp-header": "1.8.8",
     "gulp-mocha": "3.0.1",
     "gulp-rename": "1.2.2",
-    "gulp-transform": "1.0.8",
     "gulp-uglify": "2.0.0",
     "morgan": "1.7.0",
     "run-sequence": "1.2.2",