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Daniel Berger
Simon said:
You're joking a little, I know, but consider the case of Oracle.
Well, ok, Oracle PL/SQL. In Ruby, nil is false. However, in Oracle
PL/SQL you have a Boolean data type that is either true, false or null
(i.e. unknown).
Having a Boolean parent class could make object-relational mapping
layer packages, like Kansas, a bit easier (though I admit, I'm
guessing here). It could also be useful in DBI itself, where I could
retrieve data from a column with a NULL value as nil, but which
wouldn't equate to false. From there I can perform tri-state code
logic, ala PL/SQL.
For example, consider a table with a VARCHAR2(1) column called
"is_deceased" for a list of movie actors and actresses. I could
either have 'Y' or 'N' to indicate true or false. But if there's no
constraint on that column *it could also be NULL*, which is NOT the
same as false. See what I mean?
It could also be handy for that magical day when someone finally gets
around to embedding Ruby within Oracle, ala the PL/SQL Ruby module
that already exists for Postgres, or extproc_perl for Oracle.
As someone else already mentioned, it can also make unit testing
either. Instead of "is this value true or is this value false", I can
perform this operation as one "is this value a boolean". That, again,
may be useful in the database side of things.
Well, that's all I can think of for now. Maybe some other folks could
provide additional examples where it would be useful.
Just my .02
Regards,
Dan
PS - Damn - google groups doesn't seem to be picking up the ML traffic
again, so I've had to create a new thread since I don't subscribe to
the ML. My apologies.