Bumped version to 1.30 in honor of the PDP11 module that's being integrated, along with my first attempt to use a newer version of the Closure Compiler (ie, the JavaScript version), as well as giving Gulp a try -- although Gulp leaves just as bad a taste in my mouth as Grunt did

gulpfile.js

@@ -0,0 +1,120 @@
+/**
+ * @fileoverview Gulp file for pcjs.org
+ * @author <a href="mailto:Jeff@pcjs.org">Jeff Parsons</a> (@jeffpar)
+ * @version 1.0
+ * Created 2016-09-13
+ *
+ * Copyright © 2012-2016 Jeff Parsons <Jeff@pcjs.org>
+ *
+ * This file is part of PCjs, a computer emulation software project at <http://pcjs.org/>.
+ *
+ * PCjs is free software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation, either version 3
+ * of the License, or (at your option) any later version.
+ *
+ * PCjs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
+ * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with PCjs.  If not,
+ * see <http://www.gnu.org/licenses/gpl.html>.
+ *
+ * You are required to include the above copyright notice in every source code file of every
+ * copy or modified version of this work, and to display that copyright notice on every screen
+ * that loads or runs any version of this software (see COPYRIGHT in /modules/shared/lib/defines.js).
+ *
+ * Some PCjs files also attempt to load external resource files, such as character-image files,
+ * ROM files, and disk image files. Those external resource files are not considered part of PCjs
+ * for purposes of the GNU General Public License, and the author does not claim any copyright
+ * as to their contents.
+ */
+
+/*
+ * This is an experimental Gulp file; this will NOT yet build everything that Gruntfile.js builds,
+ * so for normal development, you should continue using Grunt.
+ * 
+ * To learn Gulp, I started with a simple concatenation task ("mktmp") that combines all the files
+ * required to compile a single emulation module (PCx86), and then I added a compilation task ("compile")
+ * that runs the new JavaScript version of Google's Closure Compiler.
+ * 
+ * Unfortunately, the JavaScript version of the Closure Compiler appears to be MUCH slower than the
+ * Java version.  But, it did uncover a few new type-related bugs in my code, which are now fixed,
+ * and the PCx86 emulation module now compiles successfully (although I haven't tested it yet).
+ * 
+ * Additional work is required to make Gulp skip tasks when the output file(s) are still newer
+ * than the input file(s).  By default, every time you run Gulp, EVERYTHING is built again.  Apparently,
+ * JavaScript developers think that simple declarative makefiles and automatic dependency checks are
+ * too old-fashioned.
+ */
+var gulp = require("gulp");
+var concat = require("gulp-concat");
+var foreach = require("gulp-foreach");
+var header = require("gulp-header");
+var replace = require("gulp-replace");
+var wrapper = require("gulp-wrapper");
+var sequence = require("run-sequence");
+var compiler = require('google-closure-compiler-js').gulp();
+
+var path = require("path");
+var pkg = require("./package.json");
+
+pkg.version = pkg.version.slice(0, -1) + 'x';                           // TODO: Remove this hack when we're done testing
+
+var pcX86TmpDir  = "./tmp/pcx86/"  + pkg.version;
+var pcX86ReleaseDir = "./versions/pcx86/" + pkg.version;
+var pcX86ReleaseFile  = "pcx86.js";
+
+gulp.task('mktmp', function() {
+    return gulp.src(pkg.pcX86Files)
+        .pipe(foreach(function(stream, file){
+              return stream
+                .pipe(header('/* ' + file.path + ' */\n\n'))
+                .pipe(replace(/(^|\n)[ \t]*(['"])use strict\2;?\s*/g, "$1"))
+                .pipe(replace(/[ \t]*if\s*\(NODE\)\s*(\{[^}]*}|[^\n]*)(\n|$)/gm, ""))
+                .pipe(replace(/[ \t]*if\s*\(typeof\s+(module|APP_PCJS)\s*!==\s*(['"])undefined\2\)\s*(\{[^}]*}|[^\n]*)(\n|$)/gm, ""))
+                .pipe(replace(/[ \t]*[A-Za-z_][A-Za-z0-9_.]*\.assert\([^\n]*\);[^\n]*/g, ""))
+            }))        
+        .pipe(concat(pcX86ReleaseFile))
+        .pipe(header('"use strict";\n\n'))
+        .pipe(gulp.dest(pcX86TmpDir));
+});
+
+gulp.task('compile', function() {
+    return gulp.src(path.join(pcX86TmpDir, pcX86ReleaseFile) /*, {base: './'} */)
+        /*
+         * The following DEFINE overrides are handled with a series of "--define" command-line arguments when using
+         * the Java version, but I didn't see anything analogous to that in the JavaScript version, so I'm taking a
+         * sledgehammer approach.  Note that SITEHOST should probably be extracted from the "homepage" property (or some
+         * other custom property) in package.json, rather than hard-coded below.
+         */
+        .pipe(replace(/(var\s+APPVERSION\s*=\s*)"([^"]*)"(.*)/, '$1"' + pkg.version + '"$3'))
+        .pipe(replace(/(var\s+SITEHOST\s*=\s*)"([^"]*)"(.*)/, '$1"www.pcjs.org"$3'))
+        .pipe(replace(/(var\s+COMPILED\s*=\s*)(false)(.*)/, '$1true$3'))
+        .pipe(replace(/(var\s+DEBUG\s*=\s*)(true)(.*)/, '$1false$3'))
+        .pipe(replace(/(var\s+DEBUGGER\s*=\s*)(true)(.*)/, '$1false$3'))
+        .pipe(compiler({
+            assumeFunctionWrapper: true,
+            compilationLevel: 'ADVANCED',
+            externs: [{src: 'var global; var resources;'}],             // TODO: Can this refer to "externs.js" instead?
+            warningLevel: 'VERBOSE',
+            /*
+             * outputWrapper support was recently removed (without any obvious explanation), so we take care
+             * of it below, using the gulp-wrapper plug-in.
+             * 
+             *      outputWrapper: '(function(){\n%output%\n}).call(this)',
+             */
+            jsOutputFile: pcX86ReleaseFile,                             // TODO: This must vary according to debugger/non-debugger releases
+            createSourceMap: false
+        }))
+        .pipe(wrapper({
+            header: '(function(){',
+            footer: '})();'
+        }))
+        .pipe(gulp.dest(pcX86ReleaseDir));
+});
+
+gulp.task('default', function() {
+    sequence(
+        'mktmp', 'compile'
+    );
+});