1° Using the root class TObject might be a good alternative? Storing any object within the structure is easy. Getting the object back will need a type overwrite.
2° Concerning standard structures, you might want to look at TList, TObjectList, TInterfacedList, TComponentList, TStringList which provide a lot. TStringList is very easy to use as a hash list in fact. 3° There are additional structured types in the FCL 4° You might want to read "Tomes of Delphi: Algorithms and data structures". See this link: http://www.amazon.com/Tomes-Delphi-Algorithms-Data-Structures/dp/1556227361 The source code attached is interesting. 5° You might want to investigate the generics in FPC, since thyey're very useful to build typed containers. 5° Stay away from untyped types, they're (mostly) dangerous. Basically, it means your requirements or design has not been sufficiently investigated. Using precise types in Pascal is, in fact, a huge advantage. You will have been warned. Hope this helps, Thierry Selon ik <ido...@gmail.com>: > Try the following: > > type list = ^node; > node = record > data : Variant; > next : list; > end; > > > Variant can store a lot pf data types, however please note that it's very > slow type. > You also must remember that Pascal is Strong typed, unlike C or duck type > languages. > > The Pointer type store only memory address and not the data itself, so it's > not recommended to use it unless you control the memory allocation itself > for each 'data'. > > Ido > > http://ik.homelinux.org/ > > > 2010/4/23 spir ⣠<denis.s...@gmail.com> > > > Hello, > > > > Say I want to implement a kind of linked list which node data may be > > anything. Thus I cannot store data on place (in nodes), indeed; so it > should > > be referenced. But pointers themselves are supposed to be typed. So, how > can > > I do that? > > > > type list = ^node; > > node = record > > data : ???; > > next : list; > > end; > > > > I tried to use Pointer, but then I get an error saying the compiler found > > <some type> while it expected "untyped". What is the use of Pointer > (without > > type for pointed data)? > > I also had a look at Variant; this looks like an ugly hack ;-) And avyway > > is not really generic. I need data to ba able to be anything, including > > first a linked list itself... > > Finaly, when trying to write the the algo for a given type, I get an issue > > since the def above is recursive, recursively pointing in fact. So, I need > > to stop the run somewhere by allocating the memory for non-yet-existing > data > > pointed by a pointer -- I guess. > > p^ := <I'll tell you soon, just book the place> > > (The compiler warns about not initialised pointers.) > > > > Pointers (sic!) to implementations of similar things (including trees) > > welcome... > > More generally, I cannot find in the library units for common data > > structures (sequence, associative table, set (the collection)...). > > > > Denis > > ________________________________ > > > > vit esse estrany ⣠> > > > spir.wikidot.com > > _______________________________________________ > > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > > http://lists.freepascal.org/mailman/listinfo/fpc-pascal > > > _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
