[Haskell]

[Alastair Reid]

Koji Nakahara argues that // should behave as follows

    (arr // cs1) // cs2 == arr // (cs1 ++ cs2) -- allow duplicate indices

His argument that this is what his app (and, no doubt,m others) needs is quite 
convincing - it would be useful to have an operation that behaves this way.

However, I think there's also a strong argument for having operations that 
reports an error given duplicate indices.  

Maybe we can have both sets of operations?  This could be done either using 
two separate Array types or by having two variants of a few of the array ops.

--
Alastair Reid   haskell-consulting.com