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

David Virebayre dav.vire+haskell at gmail.com
Wed Oct 13 03:31:17 EDT 2010

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

So that could be one reason.

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