NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/lang/ada/3712

Internet Message Format | 1992-12-16 | 1.9 KB

Path: sparky!uunet!usc!elroy.jpl.nasa.gov!ames!olivea!sgigate!sgi!wdl1!wdl39!mab
From: [e-mail] (Mark A Biggar)
Newsgroups: comp.lang.ada
Subject: Re: Language pitfalls (was Re: FORTRAN bug)
Message-ID: <[e-mail]>
Date: 16 Dec 92 17:27:17 GMT
References: <[e-mail]> <[e-mail]> <[e-mail]>
Sender: [e-mail]
Organization: Loral Western Development Labs
Lines: 24

In article <[e-mail]> [e-mail] (Robert I. Eachus) writes:
>In article <[e-mail]> [e-mail] (Tucker Taft) writes:
>   Oh boy.  That is a nasty one.  This argues for a "friendly"
>   Ada compiler giving a warning about any use of "null;" other
>   than the idiomatic ones like "when others => null;" or "begin null; end;"
>   (especially in a function that returns an access type ;-).
>   In retrospect, one could argue that it would have been better
>   to have no "null" statement at all (other than simply ";") than
>   to create a situation allowing this kind of one word error.
>    Actually, there is an Ada rule which normally catches this, and
>which Robert Dewar and I have argued should be removed in Ada 9X.  (A
>function must contain a return statement RM 6.5(1).)  If it belongs on
>the top ten list, then the rule should stay.
>    (What Robert Dewar and I objected to was that certain functions
>whose only intended effect is to raise an exception must still contain
>a return statement.  This results in junk return statements in stubbed
>out code, and makes a stubber much harder to write.)

How about a rule that requires a function to contain either a return or an
explisit raise statement?  Would that not satisfy both sides?

--
Mark Biggar
[e-mail]