Hi folks, I'm trying to use TH to generate parsers and writers for arbitrary datatypes. In the end I'd like every part of the declaration and generation of these functions to be automatic, but at this early stage I'm just trying to get one aspect of all that to work. So at the moment, all I want is to generate a function that exercises a parsing computation I've already defined earlier in the module: import Text.ParserCombinators.Parsec import Splices data SomeType = S Int sometype_p = do {string "S"; num <- many1 digit; return $ S (read num)} readSomeType = $(reifyDecl SomeType >>= mkLineReader) and in Splices.hs: module Splices where import Language.Haskell.THSyntax import Text.ParserCombinators.Parsec (parse) import Data.Char (toLower) modifyName f name = concat [modules, ":", f origName] where (modules, (_:origName)) = break (==':') name lower = map toLower mkLineReader :: Dec -> Q Exp mkLineReader (DataD _ name _ fields _) = do let parserName = varE $ modifyName ((++"_p").lower) name [| \line -> case parse $(parserName) line line of Left err -> error (show err) Right val -> val |] Now, when I try to compile this I get a message like so: tcLookup: `sometype_p' is not in scope In the first argument of `parse', namely `sometype_p' In the scrutinee of a case expression: parse sometype_p line'0 line'0 In the case expression: case parse sometype_p line'0 line'0 of Left err'1 -> error (show err'1) Right val'2 -> val'2 When I add -ddump-splices, it prints this in addition: \ line'0 -> case Text.ParserCombinators.Parsec.Prim.parse Main.sometype_p line'0 line'0 of Data.Either.Left err'1 -> GHC.Err.error (GHC.Show.show err'1) Data.Either.Right val'2 -> val'2 which tells me that the name sometype_p is getting built correctly, but it's just not finding the sometype_p that I've already defined. I thought that varE was the way to capture existing variables of this sort in Template Haskell, was I mistaken? What is the approved way? Or have I just missed something crucial? Thanks, Bryn