How do i replace Nodes in HXT?

问题

Given a sample xml file:

<root>
  <tag attr="value">Content</tag>
  <tag attr="value2">Content</tag>
</root>

how do i replace every tag with a different tag so i get a different file:

<root>
  <tag2 attr2="value"/>
  <tag2 attr2="value2"/>
</root>

The documentation [1] seems to use Filters, is there a way to accomplish this with arrows alone?

---

Update

i am now at the point where i can replace a node like this:

runX $ readDocument [] "in.xml" 
       >>> processTopDown( 
               (eelem "tag2" += sattr "attr2" "XXX" ) 
               `when` (isElem >>> hasName "tag") ) 
       >>> writeDocument [] "test.xml"

but i have no idea on how to get the attribute right.

---

[1] http://www.haskell.org/haskellwiki/HXT#Transform_external_references_into_absolute_reference

回答1:

Try setElemName, processAttrl, and changeAttrName from Text.XML.HXT.XmlArrow:

runX $ readDocument [] "in.xml" >>> transform >>> writeDocument [] "test.xml"
  where
    transform = processTopDown $
      ( setElemName (mkName "tag2") >>>
        processAttrl (changeAttrName $ mkName . attrMap . localPart)
      ) `when` (isElem >>> hasName "tag")
    attrMap "attr" = "attr2"
    attrMap a = a

This works for me with your sample document.

来源：https://stackoverflow.com/questions/9483248/how-do-i-replace-nodes-in-hxt