Heya Andreas, You proposed a choice between two options:
On Tue 01 Feb 2011 01:19, Andreas Rottmann <a.rottm...@gmx.at> writes: > exception-printer := port key args exception-printer -> nothing > exception-printer := port args thunk The `key' argument is necessary, at least if you want one printer to handle multiple keys (as the default printer might). I prefer the first, FWIW. > This exception registry would be used in the REPL error-handling code > primarily, via a `print-exception' procedure querying the registry and > invoking the matching printer (or the default one, if no printer is > matching). There are other cases that it would be nice to use it: in the catch-all in throw.c, and in general when printing exceptions from C. > Another open issue is the potential `frame' argument; it seems this is > only used at one place in `(system repl error-handling)', inside > `call-with-error-handling' (I did a quick grep for "display-error" and > "Throw to" to identify the sites where I'd plug in the exception > registry via the `print-exception' procedure). > > If we decide that `frame' should not be part of the exception-printer > arguments, we'd lose source information in the exception printout in > this case. Let's keep the frame out of the exception-printer functions, but still pass it to the procedure that does the exception printing dispatch (perhaps called print-exception or something). That way we can print source information, then let exception printers do their thing. > [ Just a thought: it looks like it /might/ make sense to contemplate > deprecating passing the frame information to `display-error' and > untangle displaying the exception object and displaying a backtrace > completely. ] There are certainly some tangles here. If you find The Right Thing, let us know... Andy -- http://wingolog.org/
