Hi all, This is a start at collecting X- extension fields into a parsed GenericPackageDescription and making them available through the API. I've added [(String,String)] fields to the PackageDescription and BuildInfo types, and updated the parseFields function to take an extra parameter which can optionally do something with unrecognized fields. To parse X- fields then simply requires passing a function which takes unrecognized fields starting with X- and prepends them to the list of name,value pairs in the new record fields. Everything compiles and seems to parse things without error. The only problem is that I am confused about exactly what happens to parsed BuildInfo records and how one would extract the X- fields from a GenericPackageDescription later. I know that the X-fields get parsed into PackageDescription records properly, because they now get printed out when printing out a PackageDescription; however, I've had no such luck getting that to happen with Library or Executable objects, so I'm unsure how to test to see if the parsing worked. Suggestions/comments/pointers/patches appreciated! Note that this patch should NOT be applied in its current state! In particular it definitely breaks the property specified in #155. I'm seeking advice on how to get it to a place where it can safely be applied. thanks, -Brent