Re: Limit of 255 superclasses too low?

Uli asked:
> Is that a realistic limit? Or will some more advanced projects run into
> trouble with this approach? Does anybody know what figures other
> languages (like Objective C) are working with?


To which our esteemed moderator replied:
> [Interesting question. I doubt that code written by humans would have
> hundreds of superclasses, but what about code written by other programs?
> - John]


Valid point, John, and the answer is 255 is probably a reasonable
limit, but I'm not certain. The Verilog compiler I work on emits C++
code to implement a simulator. In doing, so we generate heavily
nested classes specifically to get around some limits in the MS Visual
C++ compiler. It turns out some limitations (perhaps a limit of
65k members per class) of the compiler can be worked around by making
deep single threaded class hierarchies (e.g. 65k members per class at
each level of the chain until all the class members are included). Of
course, this is in the same application that allowed us to uncover a
MASM bug that only occurs in programs with more than 2MB of source
lines (or something similar). I don't think our current class
hierarchies have chains longer than 255 deep, but we are probably well
into the 100+ depth, and I wouldn't doubt having chains in the 200+
range by the next generation of chip that we will handle. Just like
Moore's law, the size of the simulated chips doubles with great
regularity, and at roughly the same speed, so any fixed limit (on any
attribute of the compiled code) will eventually be exceeded, and
automated source code writers will then find another limit to stretch
to cover the boundaries in the problem limit.


Hope this helps,
-Chris


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