🚀 go-pugleaf

In article <1992Aug18.045605.14220@sunb10.cs.uiuc.edu> pjl@sparc10.cs.uiuc.edu (Paul Lucas) writes:
|	To reiterate, all I would like is to guarantee that the *call*
|	to a non-virtual member-function will succeed and that it's my
|	responsibility to check for a non-nil 'this'.

First, note that this would not come at "zero" cost.  As in the case of
assigning to a reference, requiring "this" to be non-null allows compilers
to avoid generating code to preserve nullness when adjusting pointers
in the case of MI.  In the case of references, this issue has already
been reviewed and decided upon: one is not allowed to have null references.

Further, note that member functions can be called either on a pointer or
on a reference.  If the language were to PERMIT calling member functions
on a null pointer, such would not ALLOW *you* to test for null "this" inside
you member functions, but rather would REQUIRE all of *us* to test for
null "this" inside ALL *our* non-virtual member functions -- because a user
of our class such as yourself could then legally call *our* member functions via
a null pointer.  If such were the case then, the only sane remedy C++
programmers would have would be to declare all their member functions virtual.
Then *you* *still* could not legally call these members on a null pointer --
but many member functions would now be needlessly slow and generate needlessly
large code.

I suggess instead that you use friend functions or static member functions 
where you feel you must address null pointers implicitly.  Alternately, note
that the users of your class may be the ones in the best position to perform
the null pointer tests [explicitly].