[Gretl-devel] Re: special syntax for "end of matrix"

On Wed, 15 Sep 2021, Cottrell, Allin wrote: > > In current git there's a first pass at implementing this, for > > matrices. It's a bit of a hack, but a more rigorous version would be > > quite complicated. [...] > > Here's a description of what we have now. Comments welcome. > > In the current, experimental implementation of indexation from the > end, the keyword 'end' is defined as the maximum signed 32-bit integer > (INT_MAX = 2147483647). If we come across 'end-k' we replace it with > INT_MAX-k (and similarly for end/2, 0.25*end or whatever). It IS a hack, but I'd say a VERY clever one. Kudos, Allin. The only thing I found missing, after some experimentation, is the ability to use "end" for the starting element of the matric slice, as in <hansl> y = x[end-2:] </hansl> Otherwise, I haven't been able to find anything wrong with it.