Re: is OO any use?

David McNab wrote:
> Hi,
> 
> This is not a troll, so please forgive me if it comes across as such.

what is a troll?

> What I'm asking here is - is there any real practical value to be gained
> from supporting OOP in a PIC runtime environment?

when i recently did a project on 18f, i wrote the entire thing in 
assembly, and i took a very OO approach to it. because all C functions 
are automatically declared external in C18, and because a software stack 
is used rather than having any encapsulated memory allocation, i felt as 
though the principles of OO were not really available developing in C.

when i was developing in assembly, i used a methodology that was quite 
similar to OO in C++. i had an interface file which defined all external 
memory locations and sub routine names, and then i had what i termed 
'call macros' that were macros that accepted arguments and then placed 
them in memory locations specific to each module. this meant that i had 
the convenience of a 'calling' interface to my module subroutines, but 
didn't have to use the software stack. there was no inheritence, 
polymorphism etc. but by defining modules that provided interfaces to 
all the basic hardware on the PIC through subroutines with predefined 
constants used to set values in configuration registers, a certain level 
of abstraction was maintained.

i found this to be a great asset in the project. i was working with four 
others, and we were all developing completely different modules and just 
defined the interfaces between these modules. we integrated on the last 
day before the project was due virtually hassle free.

i suppose this wasn't object orientation as such, but it felt very 
object orientated (quite literally, in fact, because as our basic 
library of functions were stabilised we put them in object files and you 
just required whatever modules you needed), and i definately think that 
there is a place for object orientation on the PIC.

for example, one of the modules i developed was the UI module. i used a 
function table to respond to numeric key presses by writing directly to 
the program counter. i abstracted the modules for interpreting the 
commands, so that the same functionality was available from the keypad 
digital I/O or via hyperterminal in a serial interface. i then 
abstracted the user feedback to another module that determined whether 
information should be sent out via serial to to the LCD display module. 
i think it would be powerful to have this as a true OO abstract UI 
class, into which you can plug in different input interfaces, function 
tables, functionality and display devices to give a highly rapid and 
flexible user interface development environment that could be reused for 
virtually all PIC projects worldwide.

iain