command.coffee

# The `coffee` utility. Handles command-line compilation of CoffeeScript
# into various forms: saved into `.js` files or printed to stdout, piped to
# [JSLint](http://javascriptlint.com/) or recompiled every time the source is
# saved, printed as a token stream or as the syntax tree, or launch an
# interactive REPL.

# External dependencies.
fs             = require 'fs'
path           = require 'path'
optparse       = require './optparse'
CoffeeScript   = require './coffee-script'
helpers        = require './helpers'
{spawn, exec}  = require 'child_process'
{EventEmitter} = require 'events'

# Allow CoffeeScript to emit Node.js events, and add it to global scope.
helpers.extend CoffeeScript, new EventEmitter
global.CoffeeScript = CoffeeScript

# The help banner that is printed when `coffee` is called without arguments.
BANNER = '''
  coffee compiles CoffeeScript source files into JavaScript.

  Usage:
    coffee path/to/script.coffee
         '''

# The list of all the valid option flags that `coffee` knows how to handle.
SWITCHES = [
  ['-c', '--compile',         'compile to JavaScript and save as .js files']
  ['-i', '--interactive',     'run an interactive CoffeeScript REPL']
  ['-o', '--output [DIR]',    'set the directory for compiled JavaScript']
  ['-w', '--watch',           'watch scripts for changes, and recompile']
  ['-p', '--print',           'print the compiled JavaScript to stdout']
  ['-l', '--lint',            'pipe the compiled JavaScript through JSLint']
  ['-s', '--stdio',           'listen for and compile scripts over stdio']
  ['-e', '--eval',            'compile a string from the command line']
  ['-r', '--require [FILE*]', 'require a library before executing your script']
  ['-b', '--bare',            'compile without the top-level function wrapper']
  ['-t', '--tokens',          'print the tokens that the lexer produces']
  ['-n', '--nodes',           'print the parse tree that Jison produces']
  ['-v', '--version',         'display CoffeeScript version']
  ['-h', '--help',            'display this help message']
]

# Top-level objects shared by all the functions.
opts         = {}
sources      = []
optionParser = null

# Run `coffee` by parsing passed options and determining what action to take.
# Many flags cause us to divert before compiling anything. Flags passed after
# `--` will be passed verbatim to your script as arguments in `process.argv`
exports.run = ->
  parseOptions()
  return usage()                              if opts.help
  return version()                            if opts.version
  return require './repl'                     if opts.interactive
  return compileStdio()                       if opts.stdio
  return compileScript 'console', sources[0]  if opts.eval
  return require './repl'                     unless sources.length
  separator = sources.indexOf '--'
  flags = []
  if separator >= 0
    flags = sources.splice separator + 1
    sources.pop()
  if opts.run
    flags = sources.splice(1).concat flags
  process.ARGV = process.argv = flags
  compileScripts()

# Asynchronously read in each CoffeeScript in a list of source files and
# compile them. If a directory is passed, recursively compile all
# '.coffee' extension source files in it and all subdirectories.
compileScripts = ->
  for source in sources
    base = path.join(source)
    compile = (source, topLevel) ->
      path.exists source, (exists) ->
        throw new Error "File not found: #{source}" unless exists
        fs.stat source, (err, stats) ->
          if stats.isDirectory()
            fs.readdir source, (err, files) ->
              for file in files
                compile path.join(source, file)
          else if topLevel or path.extname(source) is '.coffee'
            fs.readFile source, (err, code) -> compileScript(source, code.toString(), base)
            watch source, base if opts.watch
    compile source, true

# Compile a single source script, containing the given code, according to the
# requested options. If evaluating the script directly sets `__filename`,
# `__dirname` and `module.filename` to be correct relative to the script's path.
compileScript = (file, input, base) ->
  o = opts
  options = compileOptions file
  if o.require
    require(if helpers.starts(req, '.') then fs.realpathSync(req) else req) for req in o.require
  try
    t = task = {file, input, options}
    CoffeeScript.emit 'compile', task
    if      o.tokens      then printTokens CoffeeScript.tokens t.input
    else if o.nodes       then console.log CoffeeScript.nodes(t.input).toString().trim()
    else if o.run         then CoffeeScript.run t.input, t.options
    else
      t.output = CoffeeScript.compile t.input, t.options
      CoffeeScript.emit 'success', task
      if o.print          then console.log t.output.trim()
      else if o.compile   then writeJs t.file, t.output, base
      else if o.lint      then lint t.output
  catch err
    # Avoid using 'error' as it is a special event -- if there is no handler,
    # node will print a stack trace and exit the program.
    CoffeeScript.emit 'failure', err, task
    return if CoffeeScript.listeners('failure').length
    return console.log err.message if o.watch
    error err.stack
    process.exit 1

# Attach the appropriate listeners to compile scripts incoming over **stdin**,
# and write them back to **stdout**.
compileStdio = ->
  code = ''
  stdin = process.openStdin()
  stdin.on 'data', (buffer) ->
    code += buffer.toString() if buffer
  stdin.on 'end', ->
    compileScript 'stdio', code

# Watch a source CoffeeScript file using `fs.watchFile`, recompiling it every
# time the file is updated. May be used in combination with other options,
# such as `--lint` or `--print`.
watch = (source, base) ->
  fs.watchFile source, {persistent: true, interval: 500}, (curr, prev) ->
    return if curr.size is prev.size and curr.mtime.getTime() is prev.mtime.getTime()
    fs.readFile source, (err, code) ->
      throw err if err
      compileScript(source, code.toString(), base)

# Write out a JavaScript source file with the compiled code. By default, files
# are written out in `cwd` as `.js` files with the same name, but the output
# directory can be customized with `--output`.
writeJs = (source, js, base) ->
  filename  = path.basename(source, path.extname(source)) + '.js'
  srcDir    = path.dirname source
  baseDir   = srcDir.substring base.length
  dir       = if opts.output then path.join opts.output, baseDir else srcDir
  jsPath    = path.join dir, filename
  compile   = ->
    js = ' ' if js.length <= 0
    fs.writeFile jsPath, js, (err) ->
      if err then console.log err.message
      else if opts.compile and opts.watch then console.log "Compiled #{source}"
  path.exists dir, (exists) ->
    if exists then compile() else exec "mkdir -p #{dir}", compile

# Pipe compiled JS through JSLint (requires a working `jsl` command), printing
# any errors or warnings that arise.
lint = (js) ->
  printIt = (buffer) -> console.log buffer.toString().trim()
  conf = __dirname + '/../extras/jsl.conf'
  jsl = spawn 'jsl', ['-nologo', '-stdin', '-conf', conf]
  jsl.stdout.on 'data', printIt
  jsl.stderr.on 'data', printIt
  jsl.stdin.write js
  jsl.stdin.end()

# Pretty-print a stream of tokens.
printTokens = (tokens) ->
  strings = for token in tokens
    [tag, value] = [token[0], token[1].toString().replace(/\n/, '\\n')]
    "[#{tag} #{value}]"
  console.log strings.join(' ')

# Use the [OptionParser module](optparse.html) to extract all options from
# `process.argv` that are specified in `SWITCHES`.
parseOptions = ->
  optionParser  = new optparse.OptionParser SWITCHES, BANNER
  o = opts      = optionParser.parse process.argv.slice 2
  o.compile     or=  !!o.output
  o.run         = not (o.compile or o.print or o.lint)
  o.print       = !!  (o.print or (o.eval or o.stdio and o.compile))
  sources       = o.arguments

# The compile-time options to pass to the CoffeeScript compiler.
compileOptions = (fileName) -> {fileName, bare: opts.bare}

# Print the `--help` usage message and exit.
usage = ->
  console.log optionParser.help()
  process.exit 0

# Print the `--version` message and exit.
version = ->
  console.log "CoffeeScript version #{CoffeeScript.VERSION}"
  process.exit 0