[Info-vax] DCL and scripting (was: Re: %PCSIUI-E-PRIVCLASS1 when using PRODUCT with PIPE)

[Stephen Hoffman]

On 2018-12-11 13:19:47 +0000, Jairo Alves said:

> When I teach simple DCL to my students they always complain about the 
> dollar sign convention. They find it kinda old-fashioned.

I usually conceptually equate the leading $ to a semicolon in C or C++, 
among those folks that have learned and programmed in those and similar 
languages; to a source code line delimiter.  There are some syntactic 
differences there, of course.

Pragmatically, DCL is very much syntactic aggregations and accretions 
perched atop a 1970s-era design, itself inspired by interactive BASIC 
shells and with a dollop or two of FORTRAN syntax that was found in a 
jar in the back of a Tewksbury 'fridge.  FORTRAN 77 was bleeding edge, 
when DCL was designed.  In short, your students are quite correct.  DCL 
itself is quite old-fashioned, and variously also quite limited.  The 
DCL design and design compromises also skew heavily toward interactive 
command input, and away from scripting and away from system and data 
access features.  Away from modern string handling, too; no regex, no 
UTF-8, string comparisons and sorting and weak case conversions with no 
localization, etc. Works decently well for basic US ASCII and DEC MCS, 
but beyond that, there'll be deep trouble.  Characters and signed 
integer 32-bit integers, etc.

If you're not already looking at it or similar tools, interactive 
Python (IPython) is a different approach with different design 
compromises and different strengths, and focuses more toward scripting 
and data access: https://ipython.org   For broader usage beyond Python 
and ilk, bash and maybe fish or another interactive shell would be more 
commonly encountered.   Microsoft also wishes PowerShell to be more 
widely installed and more commonly available, though the success of 
that open-sourcing effort remains to be seen.  For embedded scripting, 
prolly Lua.

> As a measure of precaution, I printed that out and still have this 
> guide in my desk's drawer.

It's utterly absurd that single-user mode is even remotely necessary 
for basic system and cluster configuration maintenance work; for the 
password-reset and for licensing-related "fun", and for user-startup 
troubleshooting.  The world has moved past the use of command line for 
these and similar maintenance tasks.


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