[Haskell-cafe] Exception handling when using STUArray

[Henning Thielemann]

On Wed, 12 Mar 2008, Donn Cave wrote:

> On Mar 12, 2008, at 12:32 PM, Brandon S. Allbery KF8NH wrote:
>
>> On Mar 12, 2008, at 14:17 , Donn Cave wrote:
>> 
>>> Sure.  It isn't a lot of code, so I subjected it to Either-ization
>>> as an experiment, and I did indeed take the monad procedural route.
>> 
>> Monad != procedural, unless you insist on do notation.  Think of it as 
>> composition (it may be easier to use (=<<) which "points the same 
>> direction" as (.)).
>
> Yes, I insist on do notation, because it provides a convenient
> binding form that works with what I'm doing - the original functional
> variation wasn't so suited to composition either, and used `let'.
>
> But I see that as only syntactic - equally procedural, either way.
> Expressions are evaluated in a fixed order,

Do notation only looks like there are statements that are processed from 
the beginning to the end. But that's not true, it's still purely lazy and 
expressions are evaluated in the order that is forced by data 
dependencies.

I have added this issue to
   http://haskell.org/haskellwiki/Do_notation_considered_harmful