I have uploaded a new version of the uu-parsinglib. It contains, besides the extension of the abstract interpretation part and the fixing of some very subtle corner cases in that part, some nice new functionality: The call of the parser: -- run ((,,,) `pMerge` (pSome pa <||> pMany pb <||> pOne pc <||> pNatural `pOpt` 5)) "babc45a" results in: -- > Result: (["a", "a"],["b","b"],"c",45) and -- run ((,,,) `pMerge` (pSome pa <||> pMany pb <||> pOne pc <||> pNatural `pOpt` 5)) "bbc" results in -- > Result: (["a"],["b","b"],"c",5) -- > Correcting steps: -- > Inserted 'a' at position (0,3) expecting one of ['0'..'9', 'b', 'a'] -- pSome means that the number of elements occurring in the input should be >= 1 pMany >= 0 pOne = 1 pOpt <= 1 The implementation can be found in the Derived module, and is remarkably simple. Doaitse