From: Sebastian Hungerecker <sepp2k@...>
Date: 2009-09-04T19:36:08+09:00
Subject: Re: Array.transpose on [[]] or [[],[]]

Am Freitag 04 September 2009 11:25:04 schrieb Ralf Mueller:
> sure, but [[]] has a subarray. so, shouldn't [[]].transpose have one too?

Well, [[1],[2]] has two subarrays so should [[1],[2]].transpose have two 
subarrays too?
As I said, the number of subarrays in the result equals the number of items 
per subarray in the source. I find this completely consistent.

> To point it out in a more general way: I thought, if 'transpose' can be
> applied to an array, it should behave like an involution:
> a.transpose.transpose = a.

If both [[]].transpose and [[],[]].transpose would return [[]], that still 
wouldn't be true (because then [[],[]].transpose.transpose would be [[]]).
The only way to ensure that [[],[]].transpose.transpose == [[],[]], would be 
to make transpose on an array of empty arrays to return self, which would be 
totally inconsistent with how transpose usually works.