From: Tim Hunter <cyclists@...>
Date: 2003-03-16T23:58:11+09:00
Subject: Re: vcard 0.1 - how to do return values that can have 0, 1, or >1 cardinality

In RMagick, the Image.read method reads an file that can contain 1 or
more frames (an animated GIF, for instance). The method always returns
an array of image objects. If no error occurs the array contains 1 or more
elements.

If you know you're going to be reading a file containing a single frame, you can
code

img = Magick::Image.read('mom.jpg').first

This is inelegant but better, imho, than having 2 methods, one that
returns a single image and one that returns an array of images.



On Sun, 16 Mar 2003 07:21:26 +0900, Sam Roberts wrote:

> 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