Re: [Haskell-cafe] Fixity of >>>

ross:

On Fri, Jul 27, 2007 at 12:08:30AM +1000, Donald Bruce Stewart wrote:

...

There's a theory this should work:

getContents >>= lines >>> map read >>> sum >>> print

But unfortunately we have:

`(>>=)' [infixl 1] `(>>>)' [infixr 1]

Meaning we must write:

getContents >>= (lines >>> map read >>> sum >>> print)

Indeed, all Arrow ops are infixr. Are there any technical/compelling reasons for this?

Not that I can recall. But it's the precedence rather than the associativity that's bothering you here.

Yes, I suppose it is a vote for 0.5 precedence, if they're not to behave as for >> and >>= ? Which are: infixl 1 >>, >>= So I can write: print 'x' >> getChar >>= ord >>> print -- Don