[Haskell-cafe] Solving the configuration problem with parametrized modules

Stephen Tetley stephen.tetley at gmail.com
Tue Sep 6 19:40:18 CEST 2011

On 6 September 2011 15:33, Joachim Breitner <mail at joachim-breitner.de> wrote:

> I think the benefit you get from being able to treat runtime constants
> as plain values manifests mostly when writing pure code. If your code
> has already been written or re-written in monadic style, adding a
> transformation layer is indeed less of a problem.

Run time constants are still an effect, though, just like error,
state, IO... that's why they are usually propagated with the Reader
monad or sometimes implicit params.

This does seem to irritate newcomers on Stack Overflow who don't
equate constant (but not statically known) values with more active
effects like state or file IO.

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