Who is afraid of arrows, was Re: [Haskell-cafe] ANNOUNCE: Haskell XML Toolbox Version 9.0.0

[Henning Thielemann]

David Virebayre schrieb:
> 2010/10/12 Gregory Crosswhite <gcross at phys.washington.edu>:
> 
>> Also, I don't see why one would prefer >>> over the standard function
>> composition operator, ".".
> 
> With "."  you have to read right-to-left to follow data's path.
> 
> For me that reading order isn't natural, and I imagine it is so for
> most people which don't have a mathematical background.
> 
> Combined with >>= / >> you have multiple reading direction in the same
> expression, as in
> 
> expression      ( c . b . a ) `liftM` a1 >>= a2 >>= a3
> reading order     6   5   4            1      2      3

http://www.haskell.org/haskellwiki/Direction_of_data_flow