Question about Tidy Interface

Perhaps this has been covered in the past already (if so, could someone post the related links)...

Are there any particular reasons as to why the following Node Interrogation functions require TidyDoc - when no other node or attribute functions do?

bool tidyNodeIsProp(TidyDoc tdoc, TidyNode tnod)
bool tidyNodeHasText(TidyDoc tdoc, TidyNode tnod)
bool tidyNodeGetText(TidyDoc tdoc, TidyNode tnod, TidyBuffer *buf)

I haven't delved into the source code regarding this functionality, but from an interface standpoint it seems to me that TidyNode should (in practice) contain everything that it needs to retrieve any aspect related to the Node - yet these APIs show that is not the case.

Thanks in Advance,
-Christopher M. Woods
cwoods underscore eol at yahoo dot com