Function isLine

static/js/codemirror/keymap/vim.js:283–285

(cm, line)

      return alphabetRegex.test(k);
    }
    function isLine(cm, line) {
      return line >= cm.firstLine() && line <= cm.lastLine();
    }
    function isLowerCase(k) {
      return (/^[a-z]$/).test(k);
    }