[GAP Forum] CanComputeSize

[Laurent Bartholdi]

Hi,
I try to understand Size(), HasSize() and CanComputeSize(). It seems very
strange to me that

gap> l := [];;
gap> HasSize(l);
false
gap> CanComputeSize(l);
false

isn't there a missing method/attribute here? I would expect that all dense
lists have these attributes set. However

InstallTrueMethod(CanComputeSize,IsDenseList);

doesn't change the results of the code above.

My interest is that I want to display an object either by its size (if
it exists or
is easy to compute) or as an object by itself (in other cases).

Thanks, Laurent

--
Laurent Bartholdi          \  laurent.bartholdi<at>gmail<dot>com
EPFL SB SMA IMB MAD   \    Téléphone: +41 21-6930380
CH-1015 Lausanne, Switzerland \      Fax: +41 21-6930385