The closest I came was when we went from a single namespace for all
structure names to a namespace for each structure, and references that
were checked using the pointer type of the structure pointer.
My code was a nightmare, and some of the old Unix code was at least a
bad dream. I had to start out pretending to have a single
namespace, but when I saw the use of an actual structure pointer I had
to do it the new way. As I recall when I saw something that would
not have been legal with the old rules (for example, two different
structures with the same element name but different offsets) then I
the switch and demanded the new way.
There were certainly system changes that were flash cut. For
example, changing the file system format -- there was no attempt to
allow both, which meant that the conversion program got one shot to
get it right. And it didn't always manage that...
----- Original Message -----
"Steve Johnson" <scj(a)yaccman.com>
"The Eunuchs Hysterical Society" <tuhs(a)tuhs.org>
Mon, 29 Oct 2018 12:02:29 -0700
Re: [TUHS] Archaic yacc C grammar
On Oct 29, 2018, at 10:52 AM, Steve Johnson <scj(a)yaccman.com >
We actually had a pretty good system for making changes like that.
First, we would change
the compiler to accept both the old and the new. Then we would
produce a warning
that on a particular date the old would no longer work. Then we made
the old an error
and printed a message about how to fix it. Eventually, we just let
it be a syntax error.
This process was applied many times on the way from typeless B to
strongly typed C.
Was there ever a time when a change was desired that you couldn’t
the old and the new?