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From: omullarn@oracle.oracle.com (Oliver Mullarney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MPW wish list
Keywords: MPW
Message-ID: <1990Feb9.220233.4211@oracle.com>
Date: 9 Feb 90 22:02:33 GMT
References: <1990Jan23.065751.29303@peace.waikato.ac.nz> <6310@internal.Apple.COM> <55359@hobbit.UUCP> <1990Jan25.191441.26280@oracle.com> <416@dbase.A-T.COM> <19240@dartvax.Dartmouth.EDU> <10865@claris.com>
Reply-To: omullarn@oracle.com (Oliver Mullarney)
Organization: Oracle Corporation, Belmont, CA
Lines: 41

In article <10865@claris.com> drc@claris.com (Dennis Cohen) writes:
>
>I think that a better solution for such simple errors would be one that was
>in one of the first Pascal compilers I ever used (1979). The University of
>Wisconsin's Univac 1100 compiler gave a warning message with the context and
>continued to compile, treating the source as though the semicolon were there.
>If Fischer and LeBlanc could do that on a Univac 11 or 12 years ago, it seems
>that we should have compilers that do that now.  Some errors were non-
>recoverable; however, I've missed that "friendliness" in every compiler I've
>used since then.
>
This does lead to some questions - 
What counts as a 'simple' error? There are many cases where there are a number
of possible corrections - forgetting a semi-colon may be simply that, or it
may be that the remainder of a statement was forgotten or deleted by accident.
Matching parenthesis in a logical condition can be done any number of ways,
and semantic knowledge is necessary to do it right. That's why _we_ are
still writing software, not Macs. :-)

How should compilers react to such errors? Guess?

Should the compiler modify the source file? If it does, then you will have to
go back and undo the changes if the compiler screwed up. However, if you
don't notice the warning, you will be left with a source file which compiles
correctly, even though it does not do what you intended. If the compiler
does not alter the source, then you will have to remember to go back and do
that, thereby changing the modification date and making the newly produced
application out of date with the source. Another recompile and link...

As systems get more automated, one has to very careful what one allows these
systems to do. Most of them are very stupid, especially compilers (or have I
just been using MPW C for too long :-)). Just look at the error messages you
get all the time - these machines are _really_ lost, and I for one am not
going to trust them to get me out of the woods.

 Oliver

| Oliver Mullarney     |         "Death wears a big hat,                     |
| Oracle Corporation   |          'cos he's a big bloke"                     |
| omullarn@oracle.com  |                 Tokyo Storm Warning, Elvis Costello |
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