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From: John Savard <quadibloc@servername.invalid>
Newsgroups: comp.arch
Subject: Re: ALTER, ASSIGN and labels-as-values (was: Unicode in strings)
Date: Mon, 27 May 2024 21:45:38 -0600
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On Mon, 27 May 2024 22:40:32 -0000 (UTC), "Stephen Fuld"
<SFuld@alumni.cmu.edu.invalid> wrote:

>John Savard wrote:

>> I find this to be an example of incredibly irresponsible language
>> design.

>Was it irresponsible in Fortran?

I don't understand that question. FORTRAN contained no such language
construct.

It had the computed GOTO and the assigned GOTO.

The computed GOTO was:

  GOTO (10,20,30), I

and somewhere else you would say I=2, and so it was
obvious that the GOTO could go to 10, 20, or 30 depending on how
I was set somewhere else.

That was no more irresponsible than having an IF statement in
FORTRAN.

Now, there was also the _assigned_ GOTO, and in a way one could
say that it was "closer" to what COBOL had.

The assigned GOTO was:

 GOTO LABEL,(1035,1045,1065)

and somewhere else you would say something like

 ASSIGN 1045 TO LABEL

Although this performed the same _functionality_ as the ALTER
GOTO statement in COBOL was intended for, an assigned GOTO
still obviously had multiple different destinations, based on what
was assigned to the variable LABEL somewhere else.

What was irresponsible about ALTER GOTO was that if such a
thing existed in FORTRAN, one would have

 GOTO 12

and

 ALTER GOTO 12 TO 23

somewhere else. Now _that_ would give no indication of its
presence, and it would thus be wholly confusing.

Of course, in FORTRAN, you _can_ change 12 to 23... because
pointers to constants are passed to subroutines, but that will only
smash uses of the number 12 in _calculations_, *not* 12 as
a _line number_. But that _is_ also a serious fault in FORTRAN.
Donstants should always be copied over, and only a pointer to the
copy passed to a subroutine, to allow no chance of them being
accidentally overwritten.

John Savard