From mboxrd@z Thu Jan  1 00:00:00 1970
From: doug@cs.dartmouth.edu (Doug McIlroy)
Date: Thu, 22 Mar 2018 22:53:53 -0400
Subject: [TUHS] long lived programs (was Re: RIP John Backus
Message-ID: <201803230253.w2N2rr6O005722@tahoe.cs.Dartmouth.EDU>

"The only thing I can think of is to use have programs that
translate programs in todays languages to a common but very
simple universal language for their "long term storage". May
be something like Lamport's TLA+? A very tough job.
"

Maybe not so hard. An existence proof is Brenda Baker's "struct",
which was in v7. It converted Fortran to Ratfor (which of course
turned it back to Fortran). Interestingly, authors found their
completely reorganized code easier to read than what they had
written in the first place. 

Her big discovery was a canonical form--it was not a matter of
taste or choice how the code got rearranged.

It would be harder to convert the code to say, Matlab,
because then you'd have to unravel COMMON statements and
format strings. It's easy to cook up nasty examples, like
getting away with writing behyond the end of an array, but
such things are rare in working code.

Doug