coffeescript/lib/coffeescript/repl.js

// Generated by CoffeeScript 2.0.0
(function() {
  var CoffeeScript, addHistory, addMultilineHandler, fs, getCommandId, merge, nodeREPL, path, replDefaults, runInContext, sawSIGINT, updateSyntaxError, vm;

  fs = require('fs');

  path = require('path');

  vm = require('vm');

  nodeREPL = require('repl');

  CoffeeScript = require('./');

  ({merge, updateSyntaxError} = require('./helpers'));

  sawSIGINT = false;

  replDefaults = {
    prompt: 'coffee> ',
    historyFile: (function() {
      var historyPath;
      historyPath = process.env.XDG_CACHE_HOME || process.env.HOME;
      if (historyPath) {
        return path.join(historyPath, '.coffee_history');
      }
    })(),
    historyMaxInputSize: 10240,
    eval: function(input, context, filename, cb) {
      var Assign, Block, Call, Code, Literal, Value, ast, err, isAsync, js, referencedVars, result, token, tokens;
      // 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, Call, Code} = require('./nodes'));
      try {
        // Tokenize the clean input.
        tokens = CoffeeScript.tokens(input);
        // Collect referenced variable names just like in `CoffeeScript.compile`.
        referencedVars = (function() {
          var i, len, results;
          results = [];
          for (i = 0, len = tokens.length; i < len; i++) {
            token = tokens[i];
            if (token[0] === 'IDENTIFIER') {
              results.push(token[1]);
            }
          }
          return results;
        })();
        // 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, '=')]);
        // Wrap the expression in a closure to support top-level `await`
        ast = new Code([], ast);
        isAsync = ast.isAsync;
        // Invoke the wrapping closure
        ast = new Block([new Call(ast)]);
        js = ast.compile({
          bare: true,
          locals: Object.keys(context),
          referencedVars,
          sharedScope: true
        });
        result = runInContext(js, context, filename);
        // Await an async result, if necessary
        if (isAsync) {
          result.then(function(resolvedResult) {
            if (!sawSIGINT) {
              return cb(null, resolvedResult);
            }
          });
          return sawSIGINT = false;
        } else {
          return cb(null, result);
        }
      } catch (error) {
        err = error;
        // AST's `compile` does not add source code information to syntax errors.
        updateSyntaxError(err, input);
        return cb(err);
      }
    }
  };

  runInContext = function(js, context, filename) {
    if (context === global) {
      return vm.runInThisContext(js, filename);
    } else {
      return vm.runInContext(js, context, filename);
    }
  };

  addMultilineHandler = function(repl) {
    var inputStream, multiline, nodeLineListener, origPrompt, outputStream, ref, rli;
    ({rli, inputStream, outputStream} = repl);
    // Node 0.11.12 changed API, prompt is now _prompt.
    origPrompt = (ref = repl._prompt) != null ? ref : repl.prompt;
    multiline = {
      enabled: false,
      initialPrompt: origPrompt.replace(/^[^> ]*/, function(x) {
        return x.replace(/./g, '-');
      }),
      prompt: origPrompt.replace(/^[^> ]*>?/, function(x) {
        return x.replace(/./g, '.');
      }),
      buffer: ''
    };
    // Proxy node's line listener
    nodeLineListener = rli.listeners('line')[0];
    rli.removeListener('line', nodeLineListener);
    rli.on('line', function(cmd) {
      if (multiline.enabled) {
        multiline.buffer += `${cmd}\n`;
        rli.setPrompt(multiline.prompt);
        rli.prompt(true);
      } else {
        rli.setPrompt(origPrompt);
        nodeLineListener(cmd);
      }
    });
    // Handle Ctrl-v
    return inputStream.on('keypress', function(char, key) {
      if (!(key && key.ctrl && !key.meta && !key.shift && key.name === 'v')) {
        return;
      }
      if (multiline.enabled) {
        // allow arbitrarily switching between modes any time before multiple lines are entered
        if (!multiline.buffer.match(/\n/)) {
          multiline.enabled = !multiline.enabled;
          rli.setPrompt(origPrompt);
          rli.prompt(true);
          return;
        }
        // no-op unless the current line is empty
        if ((rli.line != null) && !rli.line.match(/^\s*$/)) {
          return;
        }
        // eval, print, loop
        multiline.enabled = !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 = !multiline.enabled;
        rli.setPrompt(multiline.initialPrompt);
        rli.prompt(true);
      }
    });
  };

  // Store and load command history from a file
  addHistory = function(repl, filename, maxSize) {
    var buffer, fd, lastLine, readFd, size, stat;
    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 (stat.size > maxSize) {
        // If the history file was truncated we should pop off a potential partial line
        repl.rli.history.pop();
      }
      if (repl.rli.history[0] === '') {
        // Shift off the final blank newline
        repl.rli.history.shift();
      }
      repl.rli.historyIndex = -1;
      lastLine = repl.rli.history[0];
    } catch (error) {}
    fd = fs.openSync(filename, 'a');
    repl.rli.addListener('line', function(code) {
      if (code && code.length && code !== '.history' && code !== '.exit' && lastLine !== code) {
        // Save the latest command in the file
        fs.writeSync(fd, `${code}\n`);
        return lastLine = code;
      }
    });
    // XXX: The SIGINT event from REPLServer is undocumented, so this is a bit fragile
    repl.on('SIGINT', function() {
      return sawSIGINT = true;
    });
    repl.on('exit', function() {
      return fs.closeSync(fd);
    });
    // Add a command to show the history stack
    return repl.commands[getCommandId(repl, 'history')] = {
      help: 'Show command history',
      action: function() {
        repl.outputStream.write(`${repl.rli.history.slice(0).reverse().join('\n')}\n`);
        return repl.displayPrompt();
      }
    };
  };

  getCommandId = function(repl, commandName) {
    var commandsHaveLeadingDot;
    // Node 0.11 changed API, a command such as '.help' is now stored as 'help'
    commandsHaveLeadingDot = repl.commands['.help'] != null;
    if (commandsHaveLeadingDot) {
      return `.${commandName}`;
    } else {
      return commandName;
    }
  };

  module.exports = {
    start: function(opts = {}) {
      var build, major, minor, repl;
      [major, minor, build] = process.versions.node.split('.').map(function(n) {
        return 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.slice(2));
      opts = merge(replDefaults, opts);
      repl = nodeREPL.start(opts);
      if (opts.prelude) {
        runInContext(opts.prelude, repl.context, 'prelude');
      }
      repl.on('exit', function() {
        if (!repl.rli.closed) {
          return repl.outputStream.write('\n');
        }
      });
      addMultilineHandler(repl);
      if (opts.historyFile) {
        addHistory(repl, opts.historyFile, opts.historyMaxInputSize);
      }
      // Adapt help inherited from the node REPL
      repl.commands[getCommandId(repl, 'load')].help = 'Load code from a file into this REPL session';
      return repl;
    }
  };

}).call(this);