[fpc-pascal]method pointers, design patterns, OP idioms etc.

[memsom at interalpha.co.uk]

> I've a few questions:
> 
> 1. Is method pointers supported ? If so can anyone provide me with some 
> examples of usage. 

Yes.

type 
  MyMethodPointer = procedure(Sender: TObject) of object;

  MyclassWithMethodPointer = class
  private
    FMethodPointer: MyMethodPointer;
  public
    property MethodPointer: MyMethodPointer 
      read FMethodPointer write FMethodPointer;
  end;
 
> 2. web pointers to  idioms, design patterns etc. (I'm googling ....) In 
> particular I'm looking for the observer pattern implementation without using 
> interfaces.

This one is more tricky. Can't help you there.
 
> 3. I wrote a memory manager interface to the Boehm GC library. It compiled 
> fine but crashed during the 'mark' phase of the collection. I think I can fix 
> the problem by explicitly adding the root pointers for the collector for 
> which I need to find the absolute addresses of the data and bss segments.
> Anybody knows how to get this ? (the binutils generate labels __data_start and
> __bss_start for C programs. But code generated by FPC only has __bss_start.)

Without seeing your code it is impossible to comment with any authority. It 
sounds like you're making things overly compilcated though. If it works in C 
without this information then you probably don't need it. Otherwise, you could 
try writing a small routine to return the correct information to Pascal and add 
it to the library.

Hope that helps,

Matt

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