Luis Cabellos wrote:

...

I have a question, what's the best way to program? - put all the signatures in the Haskell Code? - Only put the type signatures needed to compile (like monomorphism errors or ambiguous signature)?

Wolfgang Jeltsch wrote:

Inserting all type signatures is definitely best practice.

(Moving to the cafe from ghc-users...) My personal style is: o Put signatures on everything at the top-level o Inside let and where, only where necessary, BUT: Inside let and where, I try to make sure that every function I define there is such that I would never want to call it separately in ghci/hugs while debugging, or in a unit test. Besides making testing and debugging easier, that rule forces the overall structure of every function to be simple and easy to read. In that case, type signatures just clutter the code and make it less readable. Conversely, if the relationship between the type of the let/where function and the type of the outer function is complex and not obvious, I will likely need to test that function. So it will go into a separate top-level function with a type signature. (I don't think this style creates any problems in Cabal.) -Yitz