[fpc-devel] interfaces vs classes in dll

[Mattias Gaertner]

On Fri, 30 Nov 2007 13:22:54 +0100 (CET)
Michael Van Canneyt <michael at freepascal.org> wrote:

> 
> 
> On Fri, 30 Nov 2007, Paul Ishenin wrote:
> 
> > Michael Van Canneyt wrote:
> > > No-one. The DLL must be recompiled anyway if you use packages.
> > > And this is also true if you use interfaces, so using interfaces
> > > will not solve the problem you mention.
> > >   
> > Only if compiler (who provides package system) changed. Ide changes
> > will not cause recompilation of plugins in case of interfaces.
> 
> Nono. If the LCL/FCL/RTL changed or whatever, then you must recompile
> the DLL as well, since it uses these packages. This will IMHO be 99%
> of all realistic cases.
> 
> If *only* the IDE interface changed, and only that, then you are
> right. But in my opinion this will be less than 1% of all possible
> cases. So the decision to use interfaces to cover this 1% is IMHO not
> founded.
> 
> It's like in Delphi.
> With each release and update of Delphi, you must recompile all
> design/runtime packages, whether the IDE interface changed or not.
> (and it uses interfaces too)

Conclusion:

A plugin without source will only work with a specific lazarus release
OR if the plugin does not share any code.

A plugin with source can be simply recompiled.

Interfaces can be more flexible when extending IDE classes. At the
moment there are only few classes where this makes sense. Maybe these
should be changed to interfaces. But the rest can remain classes.

Correct?

Mattias