Hi, On Tue 21 Aug 2012 04:36, Alex Shinn <[email protected]> writes:
>> I want them both, but given a choice I would rather have a useful >> call-with-input-file (etc) than raise-continuable, in the small r7rs. > > As Alaric points out, with call/cc people can still > write their own raise-continuable. I believe I responded to this adequately in my reply to Alaric. I think this is fine and great & stuff. Non-local exits that do not use the exception mechanism would still keep the file open, and that's super. > More generally, an exception does not mean control > won't return to the body. For example, if amb is used > anywhere inside the dynamic extent of a c-w-i-f, then > the next amb-fail will return there, even if called inside > or after an external exception handler. Exceptions are a conventional form of nonlocal exit. You can of course use other non-conventional means like amb or general call/cc. But the expectation should be that if you throw an exception, associated cleanup handlers get run, from the dynamic extent of the throw on out to the catch. > `exception-protect' is useful but is only an 80% solution. > It is therefore not appropriate for call-with-input/output-file. > We can provide `exception-protect' and possibly other > approaches in WG2, explore more options in the future, > and let users choose which is most appropriate for their > individual uses of c-w-i-f. This is ridiculous. The same argument would support not closing the file after a normal exit from the c-w-i-f procedure. Andy -- http://wingolog.org/ _______________________________________________ Scheme-reports mailing list [email protected] http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports
