🚀 go-pugleaf

In article pci@galaxy.ucr.edu, thp@PROBLEM_WITH_INEWS_DOMAIN_FILE (Tom Payne) writes:
>
>I'm voting "overworked compiler writers."  
>
>C++ does not use C's single-pass semantics for names occurring within
>a class.  Specifically, the C++ "reconsideration rule" states:
>
>   A name used in a class S must refer to the same declaration when
>   reevaluated in its context and in the completed scope of S, which
>   consists of the class S, S's base classes, and all classes enclosing
>   S.  [D&E, p.142]

The reconsideration rule requires at most two passes over a class, and a
second pass generally makes other things easier to deal with anyway.

Allowing use of an incomplete type, on the other hand, could require an
arbitrary number of passes. The original example required postponing
processing of a member type until the outer type was complete. This
postponement could be required in principle to any number of levels.

Instead of requiring this extra complexity in compilers, the language
rule requires you to use complete types where complete type data is
needed. The alternative would be to try to enumerate the cases where
an incomplete type is allowed and and where it is not. Such a rule would
be difficult to get right, difficult to understand and use. The current
rule is simple.

There is no difficulty in providing the definitions in the
correct order, and I would argue that the resulting code is easier
to read anyway. (You are entitled to a different opinion, of course.)
---
Steve Clamage, stephen.clamage@eng.sun.com