Re: Dimensions and fixed point types

["Robert I. Eachus" <rieachus@comcast.net>]

Duncan Sands wrote:

> There is no contradiction.  Not saying X is not the same
> as saying not X.  However from a practical point of view,
> any proposal to not have multiplication be auto-defined
> between fixed point numbers of the same type would
> never be accepted, since such multiplication is defined
> in the case of integer and floating point types.  So I didn't
> propose it.  That doesn't mean I think that auto-defining
> such multiplication is a good idea.  In many contexts
> multiplying two numbers of the same type makes no sense.

I have to agree with Hyman on this one.  In Ada 83 and Ada 95 
multiplication (or division) of a fixed-point parameter by Integer is 
predefined, but there is no "function "*" (L,R: _T_) return _T_" as 
there is for integer and floating-point types.

So such multiplication is not now "auto-defined".  There is the 
operation returning _universal_fixed_, and I agree that it would have 
been nice if it did not have global visibility.  Maybe it should be put 
in a package within Standard so that you have to use prefix notation or 
a use clause if you want to use it.  The operation is necessary so that 
users can define needed operations.  The original visibility wasn't bad, 
it is the added Ada 95 visibility that is a mistake.  The current 
position being discussed is a compromise.  It will make some legal Ada 
95 programs illegal, but only silly ones.

-- 

                                           Robert I. Eachus

The ideology he opposed throughout his political life insisted that 
history was moved by impersonal tides and unalterable fates. Ronald 
Reagan believed instead in the courage and triumph of free men and we 
believe it all the more because we saw that courage in him.  -- George 
W. Bush June 11, 2004