Re: catch and throw, was Is multi-level function return possible?

From	glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups	comp.compilers
Subject	Re: catch and throw, was Is multi-level function return possible?
Date	2014-03-27 19:21 +0000
Organization	Aioe.org NNTP Server
Message-ID	<14-03-072@comp.compilers> (permalink)
References	<14-03-020@comp.compilers> <14-03-023@comp.compilers> <14-03-065@comp.compilers> <14-03-068@comp.compilers> <14-03-070@comp.compilers>

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Bakul Shah <usenet@bitblocks.com> wrote:

(snip

> PL/I had ON and SIGNAL statements. SIGNAL would signal an exception.
> ON would catch it. REVERT to cancel the effect of ON. Web search
> indicates it was defined in 1964 but implemented later. May be the
> PL/I designered borrowed it from an earlier language/facility?

As mentioned earlier, some features of PL/I were implementations of
features of OS/360.

OS/360 has SPIE, Specify Program Interrupt Exit, where what they call
exit is what others would call an interrupt routine. If a program
interrupt occurs (fixed or floating point overflow, zerodivide,
illegal instruction, and such) it will call the routine at the
specified address. When that routine returns, it goes back to the
original program, possibly with registers or memory modified.

There is, then, the corresponding ON unit such as FIXEDOVERFLOW or
ZERODIVIDE.  Other exception conditions such as end of file, of even
end of page when the system counts lines on a page, can also have ON
units.

ON units stay in effect on entering different blocks, either a new
procedure or a BEGIN block. On exit from a block, any ON units on from
that block are unstacked. REVERT goes back to the one on entering the
current block.

It seems that when multitasking is used, ON units can also be
inherited by subtasks.  I am not sure at all what happens when you do
that, but I expect that it complicates the implementation.

-- glen

Thread

Is multi-level function return possible? noitalmost <noitalmost@cox.net> - 2014-03-10 15:46 -0400
  Re: Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-11 05:20 +0000
  Re: Is multi-level function return possible? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-11 13:04 +0000
    Re: Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-11 22:15 +0000
      Re: Is multi-level function return possible? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-13 17:05 +0000
        Re: Is multi-level function return possible? Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2014-03-14 01:28 +0000
        Re: Is multi-level function return possible? Ivan Godard <ivan@ootbcomp.com> - 2014-03-13 18:32 -0700
          Re: Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-14 20:27 +0000
      Re: Is multi-level function return possible? George Neuner <gneuner2@comcast.net> - 2014-03-14 02:39 -0400
        Re: Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-14 21:34 +0000
          Re: Is multi-level function return possible? Marco van de Voort <marcov@toad.stack.nl> - 2014-03-14 22:59 +0000
        Re: Is multi-level function return possible? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-16 17:19 +0000
          Re: Is multi-level function return possible? Marco van de Voort <marcov@toad.stack.nl> - 2014-03-16 18:39 +0000
          Re: Is multi-level function return possible? Andy Walker <news@cuboid.co.uk> - 2014-03-16 19:45 +0000
            Re: Is multi-level function return possible? Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2014-03-17 16:15 +0000
              Re: Is multi-level function return possible? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-18 17:36 +0000
                Re: Is multi-level function return possible? Andy Walker <news@cuboid.co.uk> - 2014-03-21 02:04 +0000
                Re: Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-21 02:50 +0000
                Re: design of PL/I, was Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-21 06:43 +0000
                Re: design of PL/I, was Is multi-level function return possible? noitalmost <noitalmost@cox.net> - 2014-03-26 14:16 -0400
                Re: exception catching in PL/I, was Is multi-level function return possible? "Robin Vowels" <robin51@dodo.com.au> - 2014-03-27 21:08 +1100
                Re: Is multi-level function return possible? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-03-24 17:06 +0000
                Re: Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-24 20:01 +0000
                Re: Is multi-level function return possible? George Neuner <gneuner2@comcast.net> - 2014-03-26 04:00 -0400
                Re: Is multi-level function return possible? Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2014-03-27 01:58 +0100
                Re: Is multi-level function return possible? Stefan Monnier <monnier@iro.umontreal.ca> - 2014-04-07 14:48 -0400
                Re: Is multi-level function return possible? Andy Walker <news@cuboid.co.uk> - 2014-03-26 12:16 +0000
                Re: Is multi-level function return possible? Andy Walker <news@cuboid.co.uk> - 2014-03-26 17:34 +0000
                Re: history of C, was Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-27 00:05 +0000
      Re: Is multi-level function return possible? Bakul Shah <usenet@bitblocks.com> - 2014-03-15 10:28 -0700
    Re: Is multi-level function return possible? George Neuner <gneuner2@comcast.net> - 2014-03-14 02:44 -0400
      Re: Is multi-level function return possible? Marco van de Voort <marcov@toad.stack.nl> - 2014-03-14 19:38 +0000
      Re: Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-14 21:36 +0000
      Re: Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-14 21:47 +0000
        Re: Is multi-level function return possible? Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2014-03-15 13:34 +0100
      Re: Is multi-level function return possible? Ian Lance Taylor <ian@airs.com> - 2014-03-14 16:55 -0700
  Re: Is multi-level function return possible? George Neuner <gneuner2@comcast.net> - 2014-03-11 13:56 -0400
    Re: Is multi-level function return possible? federation2005@netzero.com - 2014-03-26 17:39 -0700
      Re: catch and throw, was Is multi-level function return possible? rpw3@rpw3.org (Rob Warnock) - 2014-03-27 04:23 +0000
        Re: catch and throw, was Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-27 05:44 +0000
        Re: catch and throw, was Is multi-level function return possible? Bakul Shah <usenet@bitblocks.com> - 2014-03-26 23:20 -0700
          Re: catch and throw, was Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-27 19:21 +0000
          Re: exception catching in PL/I "Robin Vowels" <robin51@dodo.com.au> - 2014-03-28 10:50 +1100
            Re: exception catching in PL/I Martin Ward <martin@gkc.org.uk> - 2014-04-16 14:32 +0100
          Re: catch and throw, was Is multi-level function return possible? mac <acolvin@efunct.com> - 2014-03-28 23:08 +0000
            Re: catch and throw, was Is multi-level function return possible? Ivan Godard <ivan@ootbcomp.com> - 2014-03-28 18:24 -0700
              Re: catch and throw, was Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-29 02:47 +0000
                Re: catch and throw, was Is multi-level function return possible? Ivan Godard <ivan@ootbcomp.com> - 2014-03-28 21:32 -0700
              Re: catch and throw, was Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-29 03:38 +0000
                Re: precise and imprecise, was catch and throw, was Is multi-level function return possible? Ivan Godard <ivan@ootbcomp.com> - 2014-03-28 22:12 -0700
            Re: catch and throw, was Is multi-level function return possible? Kaz Kylheku <kaz@kylheku.com> - 2014-03-29 02:07 +0000
              Re: catch and throw, was Is multi-level function return possible? Alan Bawden <alan@scooby-doo.csail.mit.edu> - 2014-03-29 02:44 -0400
            Re: PL/I exceptions, was catch and throw, was Is multi-level function return possible? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-29 02:40 +0000
              Re: PL/I exceptions "Robin Vowels" <robin51@dodo.com.au> - 2014-03-30 01:58 +1100
      Re: catch and throw, was Is multi-level function return possible? George Neuner <gneuner2@comcast.net> - 2014-03-28 03:52 -0400
  Re: Is multi-level function return possible? Louis Krupp <lkrupp@pssw.com> - 2014-03-11 15:16 -0600
  Re: Is multi-level function return possible? noitalmost <noitalmost@cox.net> - 2014-03-15 12:21 -0400

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