RE: EXTERNAL: Re: [vhdl-200x] Update to proposal for arbitrary integers

Python (sorry to use it as an example again!) has the concept of “None” which is a metavalue used for this sort of purpose.

We could use None, Nothing, Invalid_Value, Undefined or some other similar phrase (obviously, there’s the risk of collision with historically code).

The phrase “Undefined” would have some correspondence with ‘U’ in std_logic. Hmm.  Would we then make these numerical type initialise to “Undefined” rather than type’low??

These are just “thoughts out loud” - typed before the first cup of tea of the day – I’d be interested to hear comments!

Cheers,
Martin

From: owner-vhdl-200x@eda.org [mailto:owner-vhdl-200x@eda.org] On Behalf Of Daniel Kho
Sent: 29 October 2014 08:10
To: vhdl-200x@eda.org
Subject: Re: EXTERNAL: Re: [vhdl-200x] Update to proposal for arbitrary integers

YG, Ray, all,

On 28 October 2014 07:22, <whygee@f-cpu.org<mailto:whygee@f-cpu.org>> wrote:
Furthermore NaN is not the same as "X" or "U" or "Z"...
so they could create semantic problems.


On 28 October 2014 06:44, Ray Andraka, Andraka Consulting Group, Inc <ray@andraka.com<mailto:ray@andraka.com>> wrote:
As such, I have a lot of heartburn calling this NaN.  I think that what you really want is the addition of metavalues to the integer type.
Okay, I was using the term NaN just to illustrate a problem (or problems) I have been facing again and again. It's not that I am recommending use of this term for this purpose. I am receptive to the use of any other suitable term (NAI - not-an-integer, perhaps) as long as it solves this problem.
Cheers, dan

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