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repl.coffee

A very simple Read-Eval-Print-Loop. Compiles one line at a time to JavaScript and evaluates it. Good for simple tests, or poking around the Node.js API. Using it looks like this:

coffee> console.log "#{num} bottles of beer" for num in [99..1]

             		           
                               
                            
                                
               
Require the coffee-script module to get access to the compiler.
             		                            
CoffeeScript = require './coffee-script'
helpers      = require './helpers'
readline     = require 'readline'
             		           
                               
                            
                                
               
Start by opening up stdio.
             		                            
stdio = process.openStdin()
             		           
                               
                            
                                
               
Log an error.
             		                            
error = (err) ->
  stdio.write (err.stack or err.toString()) + '\n\n'
             		           
                               
                            
                                
               
Quick alias for quitting the REPL.
             		                            
helpers.extend global, quit: -> process.exit(0)
             		           
                               
                            
                                
               
The main REPL function. run is called every time a line of code is entered.
Attempt to evaluate the command. If there's an exception, print it out instead
of exiting.
             		                            
run = (buffer) ->
  try
    val = CoffeeScript.eval buffer.toString(), bare: on, globals: on, fileName: 'repl'
    console.log val if val isnt undefined
  catch err
    error err
  repl.prompt()
             		           
                               
                            
                                
               
Make sure that uncaught exceptions don't kill the REPL.
             		                            
process.on 'uncaughtException', error
             		           
                               
                            
                                
               
Create the REPL by listening to stdin.
             		                            
repl = readline.createInterface stdio
repl.setPrompt 'coffee> '
stdio.on 'data',   (buffer) -> repl.write buffer
repl.on  'close',  -> stdio.destroy()
repl.on  'line',   run
repl.prompt()