I'd like to write some Haskell programs to manipulate comma-separated variable, .csv, files from a spreadsheet. The obvious way to start which, for perverse(?) reasons, I do not want to follow is to create a union type e.g. data CSVelement = I int | S string | ... or similar. All the elements of a given column will be of the same type e.g. bool, int, float, string, or a-selection-of-names (e.g. {Lab, Con, LibDem}). (and some columns with missing values). e.g. "Homer",42,67.8,Lab "Paris",,5.5,Con ... I'd like to write some code that 1. takes a quick look at the file, counts the columns, works out the type of each column (including creating data T1 = Lab|Con|LibDem, and using `Maybe' for missing values), 2. creates a tuple-type for a row, e.g. (String, Maybe Int, Float, T1), and adds that type to Reads, Show (and some other stuff), and 3. then gets on with processing the data. Is template-Haskell a good choice for this task and, if so, what is the quickest way to get started? (Or has it been done?) -Lloyd -- Lloyd ALLISON, CSSE, Monash University, Victoria, Australia 3800. web: http://www.csse.monash.edu.au/~lloyd/ tel: +61 3 9905 5205