RFE? request for an "undefined" attribute for functions

[Linda Walsh]

I had(have) several functions that I don't use on a regular basis (rarely), that
I had put into a subdir "func_lib" under my local-definitions directory.
This came from ksh, which allows you to define functions with an "undef" 
attribute,
and at runtime, the first time these functions were referenced,

Is this something that might have been considered for bash?  It seems like it
could have some usefulness?