diff --git a/bin/jison b/bin/jison
index 54d77affe..9ababc7bc 100755
--- a/bin/jison
+++ b/bin/jison
@@ -1,3 +1,3 @@
 #!/usr/bin/env narwhal
 
-require('jison').main(system.args);
+require('jison/cli-wrapper').main(system.args);
diff --git a/lib/jison.js b/lib/jison.js
index bba2f4dfc..152b5f5cc 100644
--- a/lib/jison.js
+++ b/lib/jison.js
@@ -1488,43 +1488,3 @@ return function Parser (g, options) {
 
 })();
 
-exports.main = function main (args) {
-    //var parser = new require("args").Parser();
-    var fs = require("file");
-        gfile = fs.path(fs.cwd()).join(args[1]);
-
-    // try to parse as JSON, else use BNF parser
-    if (gfile.extension() === '.json') {
-        var grammar = JSON.parse(gfile.read({charset: "utf-8"}));
-    } else if (gfile.extension() === '.jison') {
-        var grammar = require("jison/bnf").parse(gfile.read({charset: "utf-8"}));
-    }
-
-    var opt = grammar.options || {};
-
-    // lexer file
-    if (args[2]) {
-        var lfile = fs.path(fs.cwd()).join(args[2]);
-
-        // try to parse as JSON, else use BNF parser
-        if (lfile.extension() === '.json') {
-            grammar.lex = JSON.parse(lfile.read({charset: "utf-8"}));
-        } else if (lfile.extension() === '.jisonlex') {
-            grammar.lex = require("jison/jisonlex").parse(lfile.read({charset: "utf-8"}));
-        }
-    }
-
-    if (!opt.moduleName)
-        opt.moduleName = gfile.basename().replace(new RegExp(gfile.extension()+"$"), "");
-    if (!opt.moduleType)
-        opt.moduleType = "commonjs";
-
-    var generator = new Jison.Generator(grammar, opt);
-        fname = fs.path(fs.cwd()).join(opt.moduleName + ".js"),
-        source = generator.generate(opt),
-        stream = fname.open("w");
-
-    stream.print(source);
-    stream.close();
-};
-
diff --git a/lib/jison/cli-wrapper.js b/lib/jison/cli-wrapper.js
new file mode 100644
index 000000000..28a8481b6
--- /dev/null
+++ b/lib/jison/cli-wrapper.js
@@ -0,0 +1,34 @@
+var JISON = require('../jison');
+    IO = require('./util/io');
+
+exports.main = function (argv) {
+    var args = argv.slice(1);
+
+    if (args.length) {
+        var raw = IO.read(IO.join(IO.cwd(),args[0])),
+            name = IO.basename(args[0]).replace(/\..*$/g,''),
+            lex;
+        if (args[1]) {
+            lex = IO.read(IO.join(IO.cwd(),args[1]));
+        }
+        IO.write(name+'.js', processGrammar(raw, lex, name));
+    } else {
+        IO.stdin(function (raw) {
+            IO.stdout(processGrammar(raw));
+        });
+    }
+}
+
+function processGrammar (rawGrammar, lex, name) {
+    var grammar = require("./bnf").parse(rawGrammar);
+    var opt = grammar.options || {};
+    if (lex) grammar.lex = require("./jisonlex").parse(lex);
+    if (!opt.moduleType) opt.moduleType = "commonjs";
+    if (!opt.moduleName && name) opt.moduleName = name;
+
+    var generator = new JISON.Generator(grammar, opt);
+    return generator.generate(opt);
+}
+
+if (require.main === module)
+    exports.main(IO.args)
diff --git a/lib/jison/util/io.js b/lib/jison/util/io.js
new file mode 100644
index 000000000..a725d3f33
--- /dev/null
+++ b/lib/jison/util/io.js
@@ -0,0 +1,67 @@
+
+// node
+if (typeof process !== 'undefined') {
+
+var fs = require('fs');
+var sys = require('sys');
+
+exports.p = sys.puts;
+exports.cwd = process.cwd;
+exports.join = require('path').join;
+exports.basename = require('path').basename;
+exports.args = process.argv.slice(1);
+
+exports.read = function (fname) {
+    return fs.readFileSync(fname, "utf8");
+}
+
+exports.write = function (fname, data) {
+    fs.writeFileSync(fname, data);
+}
+
+exports.stdin = function (cb) {
+    var stdin = process.openStdin(),
+        data = '';
+
+    stdin.setEncoding('utf8');
+    stdin.addListener('data', function (chunk) {
+        data += chunk;
+    });
+    stdin.addListener('end', function () {
+        cb(data);
+    });
+}
+
+exports.stdout = function (out) {
+    process.stdout.write(out);
+}
+
+// commonjs/narwhal-like
+} else {
+
+var fs = require('file');
+var system = require('system');
+
+exports.p = print;
+exports.cwd = fs.cwd;
+exports.join = fs.join;
+exports.basename = fs.basename;
+exports.args = system.args.slice(0);
+
+exports.read = function (fname) {
+    return fs.read(fname);
+}
+
+exports.write = function (fname, data) {
+    fs.write(fname, data);
+}
+
+exports.stdin = function (cb) {
+    cb(system.stdin.read());
+}
+
+exports.stdout = function (out) {
+    system.stdout.print(out);
+}
+
+}