TCL tdom xml parsing backward until root

Question

I have a one tcl proc to write where I have given one randon node of a xml. I have to parse its parents whether they have a particular attribute field is set or not.In C++ I can easily do this using recursive function which breaks when ROOT node is reached. But in tdom I can not find how to check whether Root node has been reached or not.

/##I am just doing a rough in the following code. I wanted something like it ##
proc testRecursive {XMLnode } {
    if { $XMLnode !=ROOTNODE} { 
        set ParentND [$XMLnode parentNode]
        /#some checkings and other actions done here
        testRecursive ParentND
    } else {
        exit             
    }
}

I am new to tcl ,so syntaxs are not good, just wanted to convey the idea. How to get this result . please help.

Answer 1

It is acutally really simple:

proc testRecursive {XMLnode} {
    set parent [$XMLnode parentNode]
    if {$parent != ""} {
        # Do your checks here
        return [testRecursive $parent]
    }
    return "Default Value"
}

Just check if there is a parent node. The root node has no parent node.
You can also check if both $node root is the same as $node.