On Sun, Aug 23, 2009 at 9:25 AM, Diego Souza
Hi Alex,
- In the Token datatype, you can automatically create the accessor functions (oath_token, etc.) by using named fields: I though about that too and I was not sure about what to do. The reason I didn't use it is because I don't export the value constructors of Token type, that is why I created the access functions explicitly.
I'm pretty sure you can export just the access functions and not the data constructors. They're just ordinary functions with a bit of syntactic sugar, so they can be exported even if the constructors aren't.
- I think you can use join from Control.Monad and functions from Control.Applicative in your "response" function to make it quite a bit cleaner. To be honest I'm not familiar with Control.Applicative at all. I'll read about it and see if I can figure how to do this.
A quick search pointed me to this: http://www.soi.city.ac.uk/~ross/papers/Applicative.html
Is there any other resources you would suggest me to read?
The rule of thumb I use is that you can replace foo = do x1 <- action1 x2 <- action2 x3 <- action3 ... xn <- actionn return (bar x1 x2 x3 ... xn) by foo = bar <$> action1 <*> action2 <*> action3 <*> ... <*> actionn for any number of actions. (<$>) is a synonym for fmap and (<*>) is the same as Control.Monad.ap if the applicative functor is also a monad. (All monads can be made instances of Applicative, and most [all?] of the standard ones are.) Alex