[Haskell-cafe] Identity of indiscernibles (Was: Alternative name for return)

[Tom Ellis]

On Thu, Aug 08, 2013 at 08:41:25AM -0400, Jake McArthur wrote:
> I don't know what the denotation for this would be, but I can't think of
> any reasonable ones for which I can write (==) to respect the denotation.
> For example, is "set A, then set B" equal to "set B, then set A"?
[...]

I'm a bit lost as to what's actually being discussed in this thread, but
Jerzy seemed to suggest that the "impurity" of IO was somehow related to it
not supporting very many operations.  I was trying to point out that this
doesn't seem to be a good characterisation.  I do not, however, have a good
candidate for the definition of "impure".

Tom