diff --git a/README.md b/README.md
index ccf28e9..1ed79db 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,76 @@
 # YALI.js
-
 ### Yet Another Lox Interpreter. Javascript Implementation
 
 Lox is a Dynamically Typed Programming Language created by [Bob Nystrom](https://twitter.com/intent/user?screen_name=munificentbob) for his excellent book [Crafting Interpreters](https://craftinginterpreters.com).
 
 This is yet another Javascript Implementation.
 
-## [Try it out!](https://danman113.github.io/YALI.js/)
+## [Try it out in the Playground!](https://danman113.github.io/YALI.js/)
+
+
+## Installation
+
+```bash
+$ npm install yali.js
+```
+
+## CLI Usage
+
+### File
+```bash
+$ yali loxfile.lox
+```
+
+### REPL
+```bash
+$ yali
+> print "No semicolons needed!"
+```
+
+### loxfmt
+```bash
+$ loxfmt --write --indent="  " loxfile.lox
+```
+
+### lox2python
+```bash
+$ lox2python loxfile.lox --out="a.py"
+```
+**OR**
+```bash
+$ lox2python loxfile.lox | python
+```
+
+## Embedding in your JS App
+The main interface of YALI.js is a `run` method that will tokenize, parse, and interpret your lox source code, all in one function.
+```javascript
+run(source_code, environment = new Environment(), printfn = console.log, debug = false)
+```
+
+You can pass in an `environment` object, which lets you define built-in variables and functions like so:
+```javascript
+const { run, Environment } = require('yali')
+const env = new Environment()
+env.setBuiltin('owner', 'dberezin')
+env.setBuiltin('meaning_of_life', 42)
+env.setBuiltin('alert', (interpreter, arg) => alert(arg[0]))
+```
+
+You can also pass in a `printfn` that will be called for every `print` statement. Here's an example for capitalizing each word in the stdout:
+```javascript
+run(
+  'print "hello world";',
+  new Environment(),
+  out => console.log(out.split(' ').map(_.capitalize).join(' '))
+)
+> Hello World
+```
+
+## Parsing
+YALI.js also provides a `parse` function to tokenize and parse lox source code, returning an array of AST nodes that can be manipulated as desired. See any of the [transpiler examples](./transpilers/python) for reference.
+
+
+## Contribute
+
+For any bugs and feature requests please [open an issue](https://github.com/danman113/YALI.js/issues). For code contributions please create a [pull request](https://github.com/danman113/YALI.js/pulls). Enjoy!
+
diff --git a/examples/performance.lox b/examples/performance.lox
new file mode 100644
index 0000000..4402374
--- /dev/null
+++ b/examples/performance.lox
@@ -0,0 +1,9 @@
+fun fib(n) {
+  if (n < 2) return n;
+  return fib(n - 1) + fib(n - 2);
+}
+
+var before = clock();
+print fib(25);
+var after = clock();
+print after - before;
\ No newline at end of file
diff --git a/index.js b/index.js
index 34c5b04..c9da5f9 100755
--- a/index.js
+++ b/index.js
@@ -1,6 +1,6 @@
 const Tokenizer = require('./tokenizer')
 const Parser = require('./parser')
-const Interpreter = require('./interpreter')
+const { Interpreter, LoxClass, LoxInstance } = require('./interpreter')
 const Environment = require('./environment')
 
 const run = (code, environment, printfn, debug = false) => {
@@ -29,5 +29,10 @@ const parse = code => {
 module.exports = {
   run,
   parse,
+  Parser,
+  LoxClass,
+  Tokenizer,
+  LoxInstance,
+  Interpreter,
   Environment
 }
diff --git a/interpreter.js b/interpreter.js
index 97b50af..017b73a 100644
--- a/interpreter.js
+++ b/interpreter.js
@@ -385,4 +385,8 @@ class Interpreter {
   }
 }
 
-module.exports = Interpreter
+module.exports = {
+  Interpreter,
+  LoxClass,
+  LoxInstance
+}
diff --git a/interpreter.test.js b/interpreter.test.js
index c5bc026..d41c62b 100644
--- a/interpreter.test.js
+++ b/interpreter.test.js
@@ -1,4 +1,4 @@
-const Interpreter = require('./interpreter')
+const { Interpreter } = require('./interpreter')
 const Tokenizer = require('./tokenizer')
 const Parser = require('./parser')
 
diff --git a/transpilers/lox.js b/transpilers/lox.js
index 7a28464..7524b23 100644
--- a/transpilers/lox.js
+++ b/transpilers/lox.js
@@ -162,7 +162,7 @@ const printLoxAST = (node, scope = 0, optionsOverride = {}, initialIndent = true
     const indentation = (initialIndent ? options.indent.repeat(scope) : '')
     return indentation + ASTNodeMap.get(node.constructor)(node, scope, options)
   }
-  throw new Error(`Don't support classes yet`, node.constructor)
+  throw new Error(`Don't support classes yet`)
 }
 
 module.exports = {