Re: Signed, Unsigned syntax issues. Please help, I'm stumped

On Jun 15, 8:43=A0pm, "KJ" <kkjenni...@[EMAIL PROTECTED]
> wrote:
> "Jim Lewis" <j...@[EMAIL PROTECTED]
> wrote in message

A bit of a follwup on the previous post.  After pondering a bit more
it seems that having an optional keyword on function declarations
might do the trick.

Ex:

function foo(a, b: ufixed) return constrained ufixed;

Such a function could then query attributes of the target type to get
the info that it needs (i.e. target'left, target'right, target'range,
target'length) to do it's job.  A function without the 'constrained'
keyword would be today's ordinary function call which of course would
have to determine the range of the thing that it is going to return
based on the input parameters alone.

Ex:
function foo(a, b: ufixed) return ufixed;

These functions would be overloaded, the compiler would choose the
appropriate one based on whether or not the target has a defined range
or not.  If it did, it would call the 'constrained' version, if not it
would call the 'classic' version.

Such a method would:
- Allow for functions to be aware of attributes of the target that are
im****tant to the function, not just the base type of the target.
- Not require overloading "<=3D" or ":=3D"
- Still allow for different functions (i.e. the 'classic' version) to
exist which determine the output range based on the input ranges of
the input parameters.

It would eliminate the possibility of getting something wrong in
things where you need to provide attribute information about the
target through a separate input parameter; the classic example being

x <=3D to_unsigned(Some_Constant, x'length);

Just a thought.

Kevin Jennings