[TUHS] Public access multics

Paul Winalski paul.winalski at gmail.com
Mon Sep 3 04:18:06 AEST 2018

On 9/2/18, Dave Horsfall <dave at horsfall.org> wrote:
> I have never seen a full-blown PL/I compiler (only subsets), and I recall
> being told that there never will be one because it is simply impossible,
> given the spec.
> Naturally I am happy to be proven wrong on this.

IBM had PL/I compilers for TOS, DOS, and OS on System/360, and for
DOS/VS and OS/VS on System/370.  If those weren't full implementations
of the original spec, they were pretty close.

IBM PL/I had a good number of what I call toxic language features,
such as the DEFAULT statement (which was Fortran's IMPLICIT on
steroids).  Most PL/I shops had as part of their coding standards a
set of language features banned from the code.  The ANSI standard
eliminated a lot of these, although it also threw out some useful
features such as iSUB defining and by-name structure assignment.

One of my favourite features was sterling pictures, with pounds,
shillings, and pence fields (represented internally as a packed
decimal value in pence).  Sterling pictures weren't finally deprecated
in the IBM PL/I compilers until 1979, IIRC.

-Paul W,.

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