Re: Select + Accept syntax question

[Andrew Shvets <andrew.shvets@gmail.com>]

On Saturday, August 27, 2016 at 3:20:16 PM UTC-4, Niklas Holsti wrote:
> On 16-08-27 21:26 , Andrew Shvets wrote:
> 
> > The one thing that threw me for a loop was when I put any type of code right before the above two accept keywords, like so:
> > while Go_Loop LOOP
> >   select
> >     when Internal_Value = 0 =>
> >       Ada.Text_IO.Put_Line("hello world");
> >       accept Input(Value : in Integer) do
> >         Internal_Value := Value;
> >       end Input;
> >   or
> >     when Internal_Value /= 0 =>
> >       Ada.Text_IO.Put_Line("hello world");
> >       accept Retrieve(Value : out Integer) do
> >         Value := Internal_Value;
> >       end Retrieve;
> >
> > And I get the following output from the compiler:
> >
> >> gnatmake -g .\task_demo_11.adb
> > gcc -c -I.\ -g -I- .\task_demo_11.adb
> > task_demo_11.adb:25:16: missing "END SELECT;" for "SELECT" at line 18
> > task_demo_11.adb:25:17: select alternative ("ACCEPT", "ABORT", "DELAY") expected
> > task_demo_11.adb:38:07: "OR" not allowed here
> > task_demo_11.adb:42:07: no "SELECT" for this "END SELECT"
> > gnatmake: ".\task_demo_11.adb" compilation error
> >
> > Why does this happen?  Why can't I have code right before the accept?
> 
> Before I try to answer that question, I would like to know what 
> behaviour you expect from such code. In particular, exactly when would 
> that code be executed?
> 
> -- 
> Niklas Holsti
> Tidorum Ltd
> niklas holsti tidorum fi
>        .      @       .

To print something out and then wait for a message to arrive.