Re: Clair Grant on VMS code base

On 4/14/2025 8:45 AM, Simon Clubley wrote:

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.
>

I'd argue that such comparisons can be misleading.  As a simple example, specifying some arguments and invoking some routine.  In either case, the arguments must be specified, then invoking the routine.  Is each PUSH of an argument in assembler a separate instruction, or, just specification of an argument?  One must still specify the arguments in either case.
An example of a style I favor:
         Stat% = SYS$QIOW(       ,                       !  Event flag &
                                 ListenCh% By Value,     !  VMS channel &
                                 IO$_SETCHAR By Value,   !  Operation &
                                 IOSB::Stat%,            !  I/O status block &
                                 ,                       !  AST routine &
                                 ,                       !  AST parameter &
                                 ListenOpt::Protocol%,   !  P1 &
                                 ,                       !  P2 &
                                 ServerItemLst::Len%,    !  P3 - local socket na^
                                 BackLog% By Value,      !  P4 - connection back^
                                 SockOptItemList::Len%,  !  P5 - socket options &
                                 )                       !  P6
Ok, how many lines of code?
:-)
--
David Froble                       Tel: 724-529-0450
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