Re: A case where Ada defaults to unsafe?

[Stuart Palin <stuart.palin@baesystems.com>]

Robert A Duff wrote:
> 
> Stuart Palin <stuart.palin@baesystems.com> writes:
> > While thorough forms of testing should readily detect the 'missing'
> > reference to E, it just seems silly to introduce the risk of a simple
> > typo involving a commonly used mathematical symbol; especially when
> > there seem to be plenty of (otherwise) unused symbols available.
> 
> Which symbol(s) would you choose?

Looking at my keyboard (and without studying whether it might have been
available on some 1960's keyboard) ...

Something like '{' (I would also make a syntax error not to have the
closing '}' at the end of the line).

Some potential candidates are ruled out by the Allowable Replacement
Characters (LRM[83] 2.10 - what happened to that section in LRM[95]?). 
Something like '%' would have been nice, or even '!'; perhaps even used
in a double character token.

Other possibilities could be '~' (tilde), '@'.

Even using a '##' [OK for SPARK '###' might not be pretty ;-)] might
have been better since misuse in a based literal would (seem to) be more
readily detectable.  Of course the allowable replacement character (':')
then creates a load of other possibilities (particularly with
assignment).  But again my 'first cut' thoughts are that mistakes with
these would be more readily detectable by the compiler and (given that
most people probably don't use the replacement characters) have less
potential for messing up in the first place (= less risk of a silent
error).

Anyhow it is all water under the bridge, the die is cast - but it still
peeves me!

Regards
--
Stuart Palin
Principal Software Engineer
BAE SYSTEMS Avionics Ltd, Rochester
G-NET 791 3364    mailto:stuart.palin@baesystems.com