On Fri, Dec 25, 2009 at 5:06 PM, Serguey Zefirov
AFAIK, one of HAppS modules does a similar transformation via Template Haskell. The functions specify transactions, and each transaction is converted to a serializable data type. Then it's possible to create a transaction log by serializing them before their execution.
The happstack transaction serialization doesn't support higher-order types. Whether or not that's too much of a restriction depends on what you want your parsers to look like.
Higher-order like "data A m a = A (m a)"?
In that case, You'll be able to serialize that as long as you can serialize (m a). I meant higher-order as in function-types. So you wouldn't be able to serialize: string :: String -> Parser String Unless you had some way to reify the particular function to data. I'm also hazy on how you could encode a fully monadic expression - n applicative style parser may be a bit more modest. Antoine