Re: [sv-ec] Abstract classes and virtual methods

From: Gordon Vreugdenhil <gordonv_at_.....>
Date: Fri Jan 20 2006 - 16:51:53 PST
Steven Sharp wrote:
[...]
> Default values should match also.  This allows compilers to resolve the
> default values at compile time for efficiency, if desired.  It also
> avoids possible confusion about what default value is being used. 

Hmm - it isn't clear to me that for interesting defaults this
is possible anyway.  Consider a parameterized class that overrides
a virtual function with an expression that depends on the
class parameterization.  Very useful, but how could one determine
equivalence at compile time for anything other than a statically
typed, statically valued default?  It seems that we should
either require that only the first definition of a virtual
function is permitted to provide a default, or that general
changes are permitted.  I'm in favor of the latter since it
is likely to be more useful in the context of parameterized
classes and non-trivial type/value relationships.

Gord.



> Steven Sharp
> sharp@cadence.com
> 
> 

-- 
--------------------------------------------------------------------
Gordon Vreugdenhil                                503-685-0808
Model Technology (Mentor Graphics)                gordonv@model.com
Received on Fri Jan 20 16:51:56 2006

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