Nathan Wiger wrote:
> Let me make an observation, having done tons of matrix stuff: We're
> going to wind up with 200 functions, all of which essentially are doing
> special types of matrix operations.
>
> How about a matrix-like set of functions that interleaves and
> un-interleaves stuff however you like?
>
> matrix x2, @a, @b, @c; # interleave every 2
> unmatrix 3x2 @array; # 3x2 list groupings
>
My hope is that RFC 81: 'Lazily evaluated list generation functions'
achieves this. It provides a flexible mechanism for creating a lazily
evaluated list, with shortcuts for creating simple slices. Amongst other
things, these generated lists can be used as indices to lists in order to
extract a subset of them. From the RFC:
<quote>
This slicing notation is particularly useful for dealing with arrays,
matrices, and tensors:
@matrix = (1,3,4,
2,6,7);
@column1of3 = (1..10000:3); # (1,4,7,...10000)
print sum(@matrix[@column1of3]); # Prints 3
@matrix2 = readBig3ColumnMatrixFromSomewhere();
$column1Sum = sum(@matrix2[@column1of3]); # No need to redefine our slice!
</quote>
Of course, if we allowed infinite lists, we wouldn't need this artificial
upper bound on @column1of3 <grumble, grumble...>
Still, your matrix/unmatrix idea is intruiging... I'd be interested to see
this fleshed out further (particularly to n-dimensional tensors, which is
where I find generic functions hard to specify)...
