whole_func_string: function expandArgs(val, match, safe) {
      if (Array.isArray(val))
          return val.slice(0); // always slice to clone.
      match = match || ['"', "'"];
      safe = safe || ['[', ']', '<', '>'];
      function replacer(p, c) {
          p.a[p.a.length - 1] += c.replace(/\\(.)/, '$1');
      }
      var all = safe.concat(match);
      var result = val.match(/\\?.|^$/g).reduce(function (p, c) {
          if (~all.indexOf(c)) {
              p.quote ^= 1;
              if (~safe.indexOf(c))
                  replacer(p, c);
          }
          else if (!p.quote && c === ' ')
              p.a.push('');
          else
              replacer(p, c);
          return p;
      }, { a: [''], e: false }).a;
      return result;
  }
func_code_string: function expandArgs(val, match, safe) {
      if (Array.isArray(val))
          return val.slice(0); // always slice to clone.
      match = match || ['"', "'"];
      safe = safe || ['[', ']', '<', '>'];
      function replacer(p, c) {
          p.a[p.a.length - 1] += c.replace(/\\(.)/, '$1');
      }
      var all = safe.concat(match);
      var result = val.match(/\\?.|^$/g).reduce(function (p, c) {
          if (~all.indexOf(c)) {
              p.quote ^= 1;
              if (~safe.indexOf(c))
                  replacer(p, c);
          }
          else if (!p.quote && c === ' ')
              p.a.push('');
          else
              replacer(p, c);
          return p;
      }, { a: [''], e: false }).a;
      return result;
  }
func_documentation_string: Expand argument string into an array respecting space between special characters.
  
  NOTE: use \\ to escape inner quotes.
  
  @example 'install --dir "/some/path" -f' >> ['install', '--dir', '/some/path', '-f']
  
  @param val the arg string to split to array.
  @param match chars when matched ignore spaces withing these chars.
  @param safe same as match except these chars will be included in result.