Charles Hixson
6/1/2005 10:00:00 PM
dave wrote:
>hy list,
>
>if i have a class as:
>
>class IntegerArrray < Array
>end
>
>should i check if user inserts non Integer values ?
>
>if yes how?
>if not why?
>
>tnx.
>
>
The key question is "What is the purpose of 'IntegerArray'?".
That determines both the answers to how and why.
Frequently I'm satisfied with merely ensuring that any value returned is
a valid integer. Sometimes, however, I would want to raise an exception
if the object being added did not respond to to_i, and at other times I
would want to insist that it actually BE an Integer (well, either a
Fixnum or a Bignum).
What is the PURPOSE? That's your keystone.
If you are writing an IntegerArray in a vacuum, then there is no basis
for making a decision...but were I to do so, I would insist that every
argument respond to ".to_i", which I would apply before saving it into
the array by any means whatsoever. (And I would consider that a foolish
exercise.)
That said, I frequently find reasons to create similar entities (though
never yet an IntegerArray). Generally the reason is so that I can
store them in, e.g., a file of fixed length blocks. (Note that this is
a reason external to Ruby.) I can also see doing this so that I could
more easily handle them in a chunk of c code. (I'm not sure that this
is a good reason...I haven't tried this yet.) But I'm always doing it
for some defined purpose. (And I often rethink the approach, and try
something else.)