Re: Lack of formal syntax undermines Ada

[Gary Scott <garylscott@sbcglobal.net>]

Robert A Duff wrote:
> John McCabe <john@nospam.assen.demon.co.uk.nospam> writes:
> 
> 
>>Robert A Duff <bobduff@shell01.TheWorld.com> wrote:
>>
>>
>>>John McCabe <john@nospam.assen.demon.co.uk.nospam> writes:
>>>
>>>
>>>>As I understand it, that was deliberate; Ada's feature that functions
>>>>may not have side-effects ...
>>>
>>>Ada functions can have side effects.
>>
>>Bugger - where did I get that idea from then (have to admit, it's been
>>a while since I paid a lot of attention to Ada!)
> 
> 
> Perhaps from the fact that 'in out' and 'out' parameters are illegal for
> functions.  As Robert Dewar likes to point out, the effect of this rule
> is that functions can have side effects, so long as they are not
> properly documented.  ;-)

Sorry, non-Ada nube type question:  How is inter-language calling of 
functions that do allow inout and out arguments handled (say calling a C 
API)?  I assume the restriction only applies to intra-language calls. 
It seems like could create some messiness if the compiler always assumed 
only IN arguments in functions.

> 
> Functions can modify global variables if they are visible.
> Functions can also modify data via pointers.
> 
> - Bob


-- 

Gary Scott
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