Re: ALTER, ASSIGN and labels-as-values (was: Unicode in strings)

According to Anton Ertl <anton@mips.complang.tuwien.ac.at>:

          ...
             ALTER ALTER-1-EXIT TO PROCEED TO ALTER-2-EXIT
          END-IF.
      ALTER-1-EXIT.
          GOTO LABEL-1.

What confuses me is that there is a GOTO right in the ALTER-1-EXIT
section (or is it a procedure?).  So does the ALTER change the "GOTO
ALTER-1-EXIT" and every other occurence of "GOTO ALTER-1-EXIT" that
occurs in the program

No, it just changes that one paragraph as though it said

       ALTER-1-EXIT.
          GOTO ALTER-2-EXIT.

The program can flow into ALTER-1-EXIT in normal sequence, no need
get there by jumping.

The uniquely awful thing about ALTER was that there was no way to tell
whether any particular GOTO might be altered without reading the whole
program and looking for ALTER statements.  It was the closest thing to
COME FROM in a language that wasn't a deliberate joke.

While the FORTRAN assigned GOTO wasn't wonderful, it was at least
clear that when you wrote GO TO N the target would depend on what was
in N.

      ASSIGN 10 TO N
      ...
      GO TO N ( 10, 20, 30, 40 )

Why the strange syntax.  Why not just write
>
N = 10

See below.

People love to point out that the assigned GOTO has been removed from
Fortran, as a damnation of the concept.  But it just tells us that
Fortran programmers don't program the kind of code where this feature
is useful.

It still has computed goto which does the same thing without needing
label variables:

      GO TO (10, 42, 30), N

which says if N is 1 goto 10, if 2 goto 42, if 3 goto 30, otherwise
continue.

--
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
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