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'
util           = require 'util'
helpers        = require './helpers'
optparse       = require './optparse'
CoffeeScript   = require './coffee-script'
{spawn, exec}  = require 'child_process'
{EventEmitter} = require 'events'

# Allow CoffeeScript to emit Node.js events.
helpers.extend CoffeeScript, new EventEmitter

printLine = (line) -> process.stdout.write line + '\n'
printWarn = (line) -> process.binding('stdio').writeError line + '\n'

# The help banner that is printed when `coffee` is called without arguments.
BANNER = '''
  Usage: coffee [options] 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']
  ['-j', '--join',            'concatenate the scripts before compiling']
  ['-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']
  [      '--nodejs [ARGS]',   'pass options through to the "node" binary']
  ['-v', '--version',         'display CoffeeScript version']
  ['-h', '--help',            'display this help message']
]

# Top-level objects shared by all the functions.
opts         = {}
sources      = []
contents     = []
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 forkNode()                      if opts.nodejs
  return usage()                         if opts.help
  return version()                       if opts.version
  return require './repl'                if opts.interactive
  return compileStdio()                  if opts.stdio
  return compileScript null, sources[0]  if opts.eval
  return require './repl'                unless sources.length
  if opts.run
    opts.literals = sources.splice(1).concat opts.literals
  process.ARGV = process.argv = process.argv.slice(0, 2).concat opts.literals
  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) ->
              if opts.join
                contents[sources.indexOf source] = code.toString()
                compileJoin() if helpers.compact(contents).length is sources.length
              else
                compileScript(source, code.toString(), base)
            watch source, base if opts.watch and not opts.join
    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 printLine 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 printLine t.output.trim()
      else if o.compile   then writeJs t.file, t.output, base
      else if o.lint      then lint t.file, t.output
  catch err
    CoffeeScript.emit 'failure', err, task
    return if CoffeeScript.listeners('failure').length
    return printLine err.message if o.watch
    printWarn 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 null, code

# After all of the source files are done being read, concatenate and compile
# them together.
compileJoin = ->
  code = contents.join '\n'
  compileScript "concatenation", code, "concatenation"

# 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   = if base is '.' then srcDir else 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 printLine err.message
      else if opts.compile and opts.watch then util.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 = (file, js) ->
  printIt = (buffer) -> printLine file + ':\t' + 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}]"
  printLine 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}

# Start up a new Node.js instance with the arguments in `--nodejs` passed to
# the `node` binary, preserving the other options.
forkNode = ->
  nodeArgs = opts.nodejs.split /\s+/
  args     = process.argv[1..]
  args.splice args.indexOf('--nodejs'), 2
  spawn process.execPath, nodeArgs.concat(args),
    cwd:        process.cwd()
    env:        process.env
    customFds:  [0, 1, 2]

# Print the `--help` usage message and exit. Deprecated switches are not
# shown.
usage = ->
  printLine (new optparse.OptionParser SWITCHES, BANNER).help()
  process.exit 0

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