code: function include(ckey, file) {
      var
        match = file.match(INCNAME)
  
      file = match && match[1]
      if (file) {
        var ch = file[0]
        if ((ch === '"' || ch === "'") && ch === file.slice(-1))
          file = file.slice(1, -1).trim()
      }
      if (file) {
        result.insert = file
        result.once = !!ckey[8]
      }
      else
        emitError('Expected filename for #' + ckey + ' in @')
    }
docs: Prepares `cc` for file insertion setting the `insert` and `once` properties of `cc`. Accepts quoted or unquoted filenames