From: Sam Roberts <sroberts@...>
Date: 2003-03-16T07:21:26+09:00
Subject: Re: vcard 0.1 - how to do return values that can have 0, 1, or >1 cardinality

I used to have APIs  that returned an array, a string, or nil (if there
were multiple, 1, or no values). I  thought it was cool.

But... it turns out every time you call something you basically need a
switch to figure out what to do with it!

I also noticed that Enumrable.find_all() always returns an array, its
just sometimes it has a size of zero.

So, I've been drifting towards that.

Currently, the _all() APIs return an array, or nil, so if the return
value is true, then there is guaranteed to be at least one member, but
I'm starting to feel there's a mismatch between this way, and the Ruby
Way, so I might just always return an array for the _all() functions.
I'm still thinking about it.

What to other people do? I don't have experience with enough APIs to
know.

Cheers,
Sam

Quoteing rich@infoether.com, on Sun, Mar 16, 2003 at 05:34:48AM +0900:
> I think the index method [] returning the preferred field (if pref is 
> specified) or the first (of many) is acceptable.  I would not use the 
> index method if I wanted a full enumeration (and you provide methods 
> for that) but for quick access.  If you had two work email addresses 
> (and none were preferred) I think as long as I get one, I would be 
> happy.
> 
> if vcard[:email]
>   ...send email
> end
> 
> I would not want to have to always check for an Array vs. a String 
> thought...that would make code kind of messy.
> 
> -rich
> 
> On Saturday, March 15, 2003, at 03:18  PM, Alan Chen wrote:
> >Well, you could always return an array.
> > puts card[:email] #=> [ rich@infoether.com ]