Re: Clair Grant on VMS code base

On 2025-04-11, Arne Vajhøj <arne@vajhoej.dk> wrote:

On 4/8/2025 1:27 PM, Simon Clubley wrote:

On 2025-04-08, Arne Vajhøj <arne@vajhoej.dk> wrote:

On 4/8/2025 8:20 AM, Simon Clubley wrote:

>
It's a lot more complicated than that.
>
For example, take a LL(1) RD parser. Even ignoring the processing
of the results from the parser, how much code (and how much effort)
do you think it would take to implement it in Macro-32 compared to C ?

>
Still not obvious to me that it would not follow normal LOC/FP
ratios.

 
Try implementing one, especially with a reasonably sized grammar, and
you will very rapidly understand that it is not as simple as you seem
to think it is. :-)

>
I have not made any claim about it being simple.
>
I have made a claim that the ratio for LOC/FP for Macro-32
and LOC/FP for C for such a problem would not be significantly
different from other application types.
>

That claim is clearly incorrect.

The amount of Macro-32 code required for something higher-level such
as a RD parser that can be concisely expressed in C compared to assembly
language is clearly greater than, say a device driver, where the device
access and programming sequence is the same regardless of whether it
is done in C or assembly language.

You cannot even optimise the register access sequence in a C device driver
to reduce the amount of code, (and you even have to use volatile variables
so the compiler doesn't do it for you behind your back.)

Effort is a different issue. If someone said:
>
x1.6 LOC
x16 hours for initial write of code
x160 hours for maintenance of code
>
then I would consider it likely.
>
It has been hinted a few time that the DCL code is not easy to
understand and modify.
>

 
As I mentioned above, this is no longer about DCL. I picked the above
standalone example, a LL(1) RD parser, because it's a really good example
of the different scale of effort involved in writing it in Macro-32
instead of in C.

>
I have not made any claim about effort either.
>
Are you sure that you have understood the topic??
>

Yes, but it's not clear if you have Arne.

Simon.

--
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.