[REBOL] Re: A question of function interface design
From: mokkel:gmx at: 19-Jan-2005 15:31
> Given that Rebol is not strongly typed, is the second of these "idioms"
I thought Rebol is strongly typed (but not statically) ... like a value
has always an assigned type.
About the rest: I prefer to have the interpreter checking the types of the
arguments if that is wished. Actually I would like to have real support
for Design by Contract (pre- and postconditions and maybe
object-invariants), but I'm not sure whether that fits will with the Rebol
philosophy - but however I find in principle nothing bad in having it. I
know there is some old implementation of it at Rebol.org, but nobody seams
to use it - maybe because of some other reasons ?
I guess if you return 'none in case of error, that would somewhat destroy
the purpose of a function (some precondition is always implied - if not
explicitely stated), unless returning 'none would be raised to some
standard, but then other problems occur (like Andreas Bolka stated in the
other post). Maybe that's why I like the DBC approach, you just state
what's else implicit in the function explicitely and the user/client of
the function has to take care to fullfill the precondition and everything
will work fine.
Are there any comments regarding DBC being (un)useful for Rebol ?