brainfuck.js

#!/usr/bin/env node

'use strict';

var fs = require('fs');
var path = require('path');
var argp = require('argp');
var brainfuck = require('../lib');

var argv = argp.createParser({ once: true })
    .allowUndefinedArguments()
    .readPackage(__dirname + '/../package.json')
    .usages(['brainfuck [options] <input_file>'])
    .on('argument', function (argv, argument, ignore) {
      if (argv.file) this.fail('Too many arguments.');
      argv.file = argument;
      ignore();
    })
    .on('end', function (argv) {
      if (!argv.file) this.fail('An input file is required');
    })
    .body()
        .option({ short: 'i', long: 'input', metavar: 'STRING',
            description: 'STRING to read during the program execution' })
        .help()
    .argv();

fs.readFile(argv.file, { encoding: 'utf8' }, function (err, data) {
  if (err) {
    if (path.extname(argv.file) === '') {
      fs.readFile(argv.file + '.bf', { encoding: 'utf8' },
          function (errBf, data) {
        if (errBf) {
          // If <file>.bf doesn't exist, show <file>'s error
          return console.error('Error: ' +
              (errBf.code !== 'ENOENT' ? errBf : err).message);
        }
        brainfuck(data, argv.input);
      });
    } else {
      console.error('Error: ' + err.message);
    }
    return;
  }
  brainfuck(data, argv.input);
});