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

[Heinrich Apfelmus]

David Virebayre wrote:
> Gregory Crosswhite wrote:
> 
>> 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.

That's why I'm usually using  =<<  instead of  >>= .


Regards,
Heinrich Apfelmus

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