In Scheme, on can "quote" code, so that it becomes data. Microsoft's F# and C# 3.0 also have something similar that turns code into "expression trees". The latter is used extensively in LINQ which translates plain C# code into SQL code or any other code at runtime (this idea came from FP I heared) I can't find something similar for Haskell? Maybe I am looking at the wrong places? In Haskell, I know one can use a data constructor as a function (as in (map Just [1..3])), but a function cannot be turned into a data constructor (= "quoting"), can it? Now this is all really fuzzy for a newbie like me, because aren't all functions initially just data constructors waiting to be evaluated in a lazy language? I'm actually looking for something like (loose terminilogy follows) "context-based-semi-quoting". The idea is to only quote a set of functions, while evaluating all the others. For example, in the code 1 `add` 2 `mul` 3 where add = (+) mul = (*) I want to write something like selectiveQuote [add] (1 `add` 2 `mul` 3) which would result in an expression tree like add / \ 1 6 So the `mul` is not quoted because it is not part of the "context" = [add] Maybe this is just impossible, I did not dig deep into this. Thanks, Peter