[Haskell-cafe] Tracing Prelude.read exceptions

Hi, I got quite used to a sequence providing simple data persistence : 1) Store my data to a file: writeFile fileName (show someData) 2) Some time later read this data back: line <- readFile fileName let someData = read line :: SomeDataType Having this done hundreds of times I now got stuck with step 2) trying to read moderately complex structure back. I get read exception in run-time: fromList *** Exception: Prelude.read: no parse I have checked and rechecked my types, data files, etc. - and still no idea. So my question: Is there any way to trace Prelude.read exceptions to see exactly on what data element read fails in run-time? Thanks!