[J3] [EXTERNAL] [BULK] GNU Ada Translator GNAT has physical units checking

[Van Snyder]

On Wed, 2025-07-30 at 11:54 +0000, Clune, Thomas L. (GSFC-6101) wrote:
> Hi Van,
>  
> Templates should enable much (probably not all) of what you might
> want in terms of checking physical units.    See this paper that
> Magne presented at the Tokyo meeting:
>  
> https://j3-fortran.org/doc/year/19/19-188.pdf

The examples show that the effort is enormous, and therefore probably
wouldn't be used. The attribute system I proposed is much simpler, and
more complete, and the attributes can easily be added to existing code.

>  
> * Tom
> *  
>  
> 
> signature_2147443291
> Thomas Clune
> Lead, Software Infrastructure
> Global Modeling and Assimilation Office
> NASA Goddard Space Flight Center
> MS 610.1
> 8800 Greenbelt RD, Greenbelt, MD 20771
> Thomas.L.Clune at nasa.gov
> 
>  
>  
> From: J3 <j3-bounces at mailman.j3-fortran.org> on behalf of Van Snyder
> via J3 <j3 at mailman.j3-fortran.org>
> Date: Tuesday, July 29, 2025 at 6:08 PM
> To: j3 <j3 at j3-fortran.org>
> Cc: Van Snyder <van.snyder at sbcglobal.net>
> Subject: [EXTERNAL] [BULK] [J3] GNU Ada Translator GNAT has physical
> units checking
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> 
> 
> The GNU Ada Translator GNAT has physical units checking. See 
>  
> https://gcc.gnu.org/onlinedocs/gnat_ugn/Performing-Dimensionality-Analysis-in-GNAT.html
>  
>  
> It's not as complete as what I proposed, which was temporarily on the
> 2008 Fortran work plan.
> 
> I originally proposed in 1976 during the requirements gathering
> process for what was then called DOD/1 that it ought to include units
> declaration and checking. Colonel Whittaker wondered why a language
> explicitly designed for reliability would have a use for it.
>  
> I sent my most recent refinement, cast as a TS, to Tucker Taft, the
> head of the US delegation to the SC22/WG9 Ada committee. He said they
> are considering whether they want to extend the GNAT system and maybe
> standardize it.
>  
> Does Fortran want to reconsider a system of physical units
> declaration and checking, even if only as a TS that might never be
> standardized, or is the topic permanently off the table?
>  
> --- Van Snyder
>  

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