Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!wuarchive!cs.utexas.edu!inebriae!crucible!al
From: al@crucible.UUCP (Al Evans)
Newsgroups: comp.lang.pascal
Subject: Re: exiting some calling ancestor in Turbo Pascal 5
Summary: You gotta do it manually
Message-ID: <122@crucible.UUCP>
Date: 15 Dec 89 14:51:38 GMT
References: <8912141752.aa23459@ICS.UCI.EDU>
Reply-To: al@crucible.UUCP (Al Evans)
Followup-To: comp.lang.pascal
Organization: PowerTools, Austin, TX
Lines: 49

In article <8912141752.aa23459@ICS.UCI.EDU> milne@ICS.UCI.EDU (Alastair Milne) writes:

[description of need for multi-level "EXIT" deleted....]

>   Turbo Pascal gives only, as far as I know, EXIT (which exits the immediate
>   block, but nothing further) and HALT (which kills the whole program).
>   Does anybody know of a way in Turbo Pascal to obtain the effect of UCSD
>   Pascal's EXIT?

I wish there were. Actually, in UCSD, I think you can even exit procedures
that HAVEN'T been called -- this gives interesting results. I do things
as shown below, in about 60K lines of Pascal that exists under both Turbo and
UCSD (don't ask:-).

PROCEDURE BigBlock
VAR exitFlag: BOOLEAN;

PROCEDURE SubProcA;
BEGIN
  ...
  {Condition requiring exit from main block found}
  exitFlag:= TRUE;
  EXIT;
  ...
END;

PROCEDURE SubProcB;
BEGIN
  ...
  SubProcA;
  IF exitFlag THEN EXIT;
  ...
END;

BEGIN {BigBlock}
  exitFlag:= FALSE;
  ...
  SubProcB;
  IF exitFlag THEN EXIT;
  ...
END;

It ain't pretty, but it's the only way I've found to accomplish a multilevel
exit under Turbo Pascal.
					--Al Evans--
-- 
Al Evans					"You'd grep to know what
...uunet!execu!sequoia!crucible!al			 you really sed."
							--Referent Blob