Finding and Iterating Nodes

The mxmlWalkPrev() and mxmlWalkNext() functions can be used to iterate through the XML node tree:

    mxml_node_t *node = mxmlWalkPrev(current, tree, MXML_DESCEND);

    mxml_node_t *node = mxmlWalkNext(current, tree, MXML_DESCEND);

In addition, you can find a named element/node using the mxmlFindElement() function:

    mxml_node_t *node = mxmlFindElement(tree, tree, "name", "attr",
                                	"value", MXML_DESCEND);

The name, attr, and value arguments can be passed as NULL to act as wildcards, e.g.:

    /* Find the first "a" element */
    node = mxmlFindElement(tree, tree, "a", NULL, NULL, MXML_DESCEND);

    /* Find the first "a" element with "href" attribute */
    node = mxmlFindElement(tree, tree, "a", "href", NULL, MXML_DESCEND);

    /* Find the first "a" element with "href" to a URL */
    node = mxmlFindElement(tree, tree, "a", "href",
                	   "http://www.easysw.com/~mike/mxml/", MXML_DESCEND);

    /* Find the first element with a "src" attribute*/
    node = mxmlFindElement(tree, tree, NULL, "src", NULL, MXML_DESCEND);

    /* Find the first element with a "src" = "foo.jpg" */
    node = mxmlFindElement(tree, tree, NULL, "src", "foo.jpg", MXML_DESCEND);

You can also iterate with the same function:

    mxml_node_t *node;

    for (node = mxmlFindElement(tree, tree, "name", NULL, NULL, MXML_DESCEND);
         node != NULL;
         node = mxmlFindElement(node, tree, "name", NULL, NULL, MXML_DESCEND))
    {
      ... do something ...
    }

The MXML_DESCEND argument can actually be one of three constants:

• MXML_NO_DESCEND means to not to look at any child nodes in the element hierarchy, just look at siblings at the same level or parent nodes until the top node or top-of-tree is reached. The previous node from "group" would be the "node" element to the left, while the next node from "group" would be the "node" element to the right.
• MXML_DESCEND_FIRST means that it is OK to descend to the first child of a node, but not to descend further when searching. You'll normally use this when iterating through direct children of a parent node, e.g. all of the "node" elements under the "?xml" parent node in the example above. This mode is only applicable to the search function; the walk functions treat this as MXML_DESCEND since every call is a first time.
• MXML_DESCEND means to keep descending until you hit the bottom of the tree. The previous node from "group" would be the "val3" node and the next node would be the first node element under "group". If you were to walk from the root node "?xml" to the end of the tree with mxmlWalkNext(), the order would be:

      ?xml
      data
      node
      val1
      node
      val2
      node
      val3
      group
      node
      val4
      node
      val5
      node
      val6
      node
      val7
      node
      val8
      node
      val9
  

  If you started at "val9" and walked using mxmlWalkPrev(), the order would be reversed, ending at "?xml".