repl.coffee

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  browser.coffee cake.coffee coffeescript.coffee command.coffee grammar.coffee helpers.coffee index.coffee lexer.coffee nodes.coffee optparse.coffee register.coffee repl.coffee rewriter.coffee scope.litcoffee sourcemap.litcoffee

- # repl.coffee

- ¶

      fs = require 'fs'
      path = require 'path'
      vm = require 'vm'
      nodeREPL = require 'repl'
      CoffeeScript = require './'
      {merge, updateSyntaxError} = require './helpers'

      replDefaults =
        prompt: 'coffee> ',
        historyFile: do ->
          historyPath = process.env.XDG_CACHE_HOME or process.env.HOME
          path.join historyPath, '.coffee_history' if historyPath
        historyMaxInputSize: 10240
        eval: (input, context, filename, cb) ->

- ¶

  XXX: multiline hack.

          input = input.replace /\uFF00/g, '\n'

- ¶

  Node’s REPL sends the input ending with a newline and then wrapped in parens. Unwrap all that.

          input = input.replace /^\(([\s\S]*)\n\)$/m, '$1'

- ¶

  Node’s REPL v6.9.1+ sends the input wrapped in a try/catch statement. Unwrap that too.

          input = input.replace /^\s*try\s*{([\s\S]*)}\s*catch.*$/m, '$1'

- ¶

  Require AST nodes to do some AST manipulation.

          {Block, Assign, Value, Literal} = require './nodes'

          try

- ¶

  Tokenize the clean input.

            tokens = CoffeeScript.tokens input

- ¶

  Collect referenced variable names just like in `CoffeeScript.compile`.

            referencedVars = (
              token[1] for token in tokens when token[0] is 'IDENTIFIER'
            )

- ¶

  Generate the AST of the tokens.

            ast = CoffeeScript.nodes tokens

- ¶

  Add assignment to `_` variable to force the input to be an expression.

            ast = new Block [
              new Assign (new Value new Literal '__'), ast, '='
            ]
            js = ast.compile {bare: yes, locals: Object.keys(context), referencedVars}
            cb null, runInContext js, context, filename
          catch err

- ¶

  AST’s `compile` does not add source code information to syntax errors.

            updateSyntaxError err, input
            cb err

      runInContext = (js, context, filename) ->
        if context is global
          vm.runInThisContext js, filename
        else
          vm.runInContext js, context, filename

      addMultilineHandler = (repl) ->
        {rli, inputStream, outputStream} = repl

- ¶

  Node 0.11.12 changed API, prompt is now _prompt.

        origPrompt = repl._prompt ? repl.prompt

        multiline =
          enabled: off
          initialPrompt: origPrompt.replace /^[^> ]*/, (x) -> x.replace /./g, '-'
          prompt: origPrompt.replace /^[^> ]*>?/, (x) -> x.replace /./g, '.'
          buffer: ''

- ¶

  Proxy node’s line listener

        nodeLineListener = rli.listeners('line')[0]
        rli.removeListener 'line', nodeLineListener
        rli.on 'line', (cmd) ->
          if multiline.enabled
            multiline.buffer += "#{cmd}\n"
            rli.setPrompt multiline.prompt
            rli.prompt true
          else
            rli.setPrompt origPrompt
            nodeLineListener cmd
          return

- ¶

  Handle Ctrl-v

        inputStream.on 'keypress', (char, key) ->
          return unless key and key.ctrl and not key.meta and not key.shift and key.name is 'v'
          if multiline.enabled

- ¶

  allow arbitrarily switching between modes any time before multiple lines are entered

            unless multiline.buffer.match /\n/
              multiline.enabled = not multiline.enabled
              rli.setPrompt origPrompt
              rli.prompt true
              return

- ¶

  no-op unless the current line is empty

            return if rli.line? and not rli.line.match /^\s*$/

- ¶

  eval, print, loop

            multiline.enabled = not multiline.enabled
            rli.line = ''
            rli.cursor = 0
            rli.output.cursorTo 0
            rli.output.clearLine 1

- ¶

  XXX: multiline hack

            multiline.buffer = multiline.buffer.replace /\n/g, '\uFF00'
            rli.emit 'line', multiline.buffer
            multiline.buffer = ''
          else
            multiline.enabled = not multiline.enabled
            rli.setPrompt multiline.initialPrompt
            rli.prompt true
          return

- ¶

  Store and load command history from a file

      addHistory = (repl, filename, maxSize) ->
        lastLine = null
        try

- ¶

  Get file info and at most maxSize of command history

          stat = fs.statSync filename
          size = Math.min maxSize, stat.size

- ¶

  Read last `size` bytes from the file

          readFd = fs.openSync filename, 'r'
          buffer = Buffer.alloc size
          fs.readSync readFd, buffer, 0, size, stat.size - size
          fs.closeSync readFd

- ¶

  Set the history on the interpreter

          repl.rli.history = buffer.toString().split('\n').reverse()

- ¶

  If the history file was truncated we should pop off a potential partial line

          repl.rli.history.pop() if stat.size > maxSize

- ¶

  Shift off the final blank newline

          repl.rli.history.shift() if repl.rli.history[0] is ''
          repl.rli.historyIndex = -1
          lastLine = repl.rli.history[0]

        fd = fs.openSync filename, 'a'

        repl.rli.addListener 'line', (code) ->
          if code and code.length and code isnt '.history' and code isnt '.exit' and lastLine isnt code

- ¶

  Save the latest command in the file

            fs.writeSync fd, "#{code}\n"
            lastLine = code

        repl.on 'exit', -> fs.closeSync fd

- ¶

  Add a command to show the history stack

        repl.commands[getCommandId(repl, 'history')] =
          help: 'Show command history'
          action: ->
            repl.outputStream.write "#{repl.rli.history[..].reverse().join '\n'}\n"
            repl.displayPrompt()

      getCommandId = (repl, commandName) ->

- ¶

  Node 0.11 changed API, a command such as ‘.help’ is now stored as ‘help’

        commandsHaveLeadingDot = repl.commands['.help']?
        if commandsHaveLeadingDot then ".#{commandName}" else commandName

      module.exports =
        start: (opts = {}) ->
          [major, minor, build] = process.versions.node.split('.').map (n) -> parseInt(n, 10)

          if major < 6
            console.warn "Node 6+ required for CoffeeScript REPL"
            process.exit 1

          CoffeeScript.register()
          process.argv = ['coffee'].concat process.argv[2..]
          opts = merge replDefaults, opts
          repl = nodeREPL.start opts
          runInContext opts.prelude, repl.context, 'prelude' if opts.prelude
          repl.on 'exit', -> repl.outputStream.write '\n' if not repl.rli.closed
          addMultilineHandler repl
          addHistory repl, opts.historyFile, opts.historyMaxInputSize if opts.historyFile

- ¶

  Adapt help inherited from the node REPL

          repl.commands[getCommandId(repl, 'load')].help = 'Load code from a file into this REPL session'
          repl