[xml] Why doesn't xmlAddChild unlink the node first?

[Bertrand Fritsch <bfr 4js com>]

Hi,

I wonder why the xmlAddChild function doesn't unlink the node before 
adding it to the tree, whereas xmlAddNextSibling and xmlAddSibling 
functions do it? What is the rationale behind this? From a caller POV, 
the difference is compelling since the work to do to call these function 
is not the same in one case than in the other.

Thanks,
Bertrand.