Function compile

06.Router/basic/js/vue.js:6878–6907

* Compile a template and return a reusable composite link * function, which recursively contains more link functions * inside. This top level compile function would normally * be called on instance root nodes, but can also be used * for partial compilation if the partial argument is true

(el, options, partial)

   */

  function compile(el, options, partial) {
    // link function for the node itself.
    var nodeLinkFn = partial || !options._asComponent ? compileNode(el, options) : null;
    // link function for the childNodes
    var childLinkFn = !(nodeLinkFn && nodeLinkFn.terminal) && !isScript(el) && el.hasChildNodes() ? compileNodeList(el.childNodes, options) : null;

    /**
     * A composite linker function to be called on a already
     * compiled piece of DOM, which instantiates all directive
     * instances.
     *
     * @param {Vue} vm
     * @param {Element|DocumentFragment} el
     * @param {Vue} [host] - host vm of transcluded content
     * @param {Object} [scope] - v-for scope
     * @param {Fragment} [frag] - link context fragment
     * @return {Function|undefined}
     */

    return function compositeLinkFn(vm, el, host, scope, frag) {
      // cache childNodes before linking parent, fix #657
      var childNodes = toArray(el.childNodes);
      // link
      var dirs = linkAndCapture(function compositeLinkCapturer() {
        if (nodeLinkFn) nodeLinkFn(vm, el, host, scope, frag);
        if (childLinkFn) childLinkFn(vm, childNodes, host, scope, frag);
      }, vm);
      return makeUnlinkFn(vm, dirs);
    };
  }

  /**
   * Apply a linker to a vm/element pair and capture the