From: rgenter@BBN-LABS-B.ARPA
Subject: Re: More fun with public domain Ada
Date: Wed, 29-Jan-86 14:48:49 EST [thread overview]
Date: Wed Jan 29 14:48:49 1986
Message-ID: <8601300024.AA00511@ucbvax.berkeley.edu> (raw)
In-Reply-To: 8601291840.AA27130@cod.ARPA
In article <8601291840.AA27130@cod.ARPA> David B. Collom
<sdcsvax!noscvax!collom@ucbvax.berkeley.EDU> writes:
> In article <8601210108.AA00678@ucbvax.berkeley.edu> you write:
> >
> > . . .
> >
> > One program had the following statement (without the comment!)
> >
> > LNTH : NATURAL range 1..8 := 0; --whoops, can't count
> >
> > [ worry that it compiled OK then failed at run time ]
>
> According to one textbook I have:
>
> ...there is a general principle that a declaration with
> initial value
> A: T:=I;
> is essentially equivalent to
> A: T;
> ...
> A:=I;
> in which the declaration is given without the initial value
> and is then followed by an assignment statement.
>
> [ includes a quote from Section 3.2.1 of the ARM and concludes that Ada
> only requires a run-time check, not a compile-time check ]
>
> David Collom
>
> (All opinions expressed are my own.)
Perhaps the ARM doesn't *require* that compile-time checking be performed,
but I would certainly hope that
Lnth: NATURAL range 1..8;
Lnth := 0;
would be caught at compile-time. It doesn't take a whole lot more intelligence
to figure out that the above is invalid, given that the following is also
invalid (and *is* a compile-time error even in the ARM):
Lnth := 1.5;
--------
Rick Genter BBN Laboratories Inc.
(617) 497-3848 10 Moulton St. 6/506
rgenter@labs-b.bbn.COM (Internet new) Cambridge, MA 02238
rgenter@bbn-labs-b.ARPA (Internet old) ...!{decvax,linus}!bbncca!rgenter (UUCP)
next prev parent reply other threads:[~1986-01-29 19:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
1986-01-21 0:26 More fun with public domain Ada Jerry Mungle
1986-01-29 18:40 ` info-ada
1986-01-29 19:48 ` rgenter [this message]
1986-01-30 17:06 ` info-ada
-- strict thread matches above, loose matches on Subject: below --
1986-01-30 16:53 David B. Collom
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