> 
> William Chops" Westfield" wrote:
> 
> > Please provide a pascal example that works with at least 
> two different 
> > vendors' pascal compilers.
> 
> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Olin Lathrop
> Sent: 02 July 2009 01:00
> To: Microcontroller discussion list - Public.
> Subject: Re: [PIC] using BREAK in 'C'
>
> No, you're missing the point again.  We're talking about 
> computer science concepts, not particular implementations.  
> The point is that what you want to do is possible in a more 
> tightly typed language like Pascal.  A single instance is 
> proof enough.

I think you are missing Bills point.  Can you take the code you have
just written and be sure it will compile and work on any arbitrary
Pascal compiler?  Would you really want to have to have a diffierent
implementaion of this code for each target you want to use it on?

Most of the projects I work on keep the CPU pretty busy with a lot of
completely separate tasks, but since we don't use an RTOS, each task is
impleneted using a state machine.  All variables that are only used by
the task (e.g. the timer and state variable) are declared static within
the task function, since they need to retain their values between calls.

#define MY_TASK_PERIOD_MS 15

void MyTask( void ) {
    static int my_task_state = 0;
    static tickms_t mytask_time;

    switch( my_task_state ) {
        case 0:
            /* Initialise timer */
            mytask_time = StartTimer( MY_TASK_PERIOD_MS );
            my_task_state = 1;
            break;

        case 1:
            /* new state dpends on function return */
            my_task_state = ( MyFunc() )? 2 : 3;
            break;
        
        case 2:
            /* some stuff */
            break;

        case 3:
            /* some other stuff */
            break;

        case 4:
            if( TimerExpired( mytask_time ) ) {
			mytask_time = StartTimer( MY_TASK_PERIOD_MS );
			my_task_state = 1;
            }
            break;

        /* etc...etc... */
    }
}

When I last used Pascal (a long time ago admittedly), I could find no
way of defining static variables within a function, so end up using
globals which is very ugly.  Has this situation changed?

Regards

Mike

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