Re: GNAT and Tasklets

[Brad Moore <brad.moore@shaw.ca>]

On 14-12-21 04:21 PM, Shark8 wrote:
> On 21-Dec-14 12:45, Brad Moore wrote:
>>>> I have never seen a programming language that has parameters on an if
>>>> statement.
>>>
>>> But all if-statements have a parameter: the conditional they test.
>>
>> Not the sort of parameters we have been discussing though. Parameters
>> that identify all the external variables that are read and/or modified
>> inside the if statement.
>
> True.
> Maybe we could overload WITH or AT, or perhaps have an optional area
> [like declare] to be explicit about them?

Note also, if we start allowing this to be specified for if statements, 
you'd also want to allow for other constructs such as while loops, 
normal blocks, etc, as well as subprograms.

What we were proposing is to just allow this for subprograms. 
Subprograms already identify parameters in this way, but in addition we 
were proposing adding a Global aspect that could be applied to 
subprograms that identifies the side effects on external variables.

Subprograms already allow aspects, so this fits in well with existing 
syntax, whereas statements such as if statements, loop statements, and 
block statements, do not currently allow aspects in the syntax, so 
adding aspect support for those is a bigger change.

I also think it would become too tedious and add too much clutter and 
noise to the readability of the code if we start specifying these 
effects on all types of statements. Being able to do this on subprograms 
feels to me like the happier middle ground.