If it were an oft-used pair, I'd probably make a struct to hold them together, but if it's a just-this-one-method, just-this-one-time thing I'd settle with a Dictionary.
Of course, you do have one more option: pass-by-reference or pointer. I've never been a big fan, personally, because I prefer to break methods into more discrete blocks and limit side effects, but it is an option and it's arguably more self-documenting. J -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] ] On Behalf Of James Montgomerie Sent: Wednesday, July 02, 2008 2:48 PM To: Cocoa-Dev List Subject: A question of style: Returning 'pairs' Say I have a method that needs to return two equally important values (in my case, a string and an offset into it). I am overthinking how to do it, and I though it would be interesting to see what others have done. I see these opportunities (my use of 'object' and 'value' is blurred below, since I'm thinking of the abstract case - assume that both values could be objects): 1) Just return the first value, and have the caller supply an argument that the second value gets written into (akin to how NSError is customarily used). This seems a bit unclean, since one value is not more important than the other, and both are necessarily returned. 2) Define a custom C struct (like NSRect, but with e.g. 'string' and 'offset' members) and return objects in it. Just like any other returned objects, the caller would be expected to retain them individually if it needed to keep them around. 3) Define a custom Obj-C class with two properties [e.g. 'string' and 'offset'] and return an object of that class (with properties appropriately set). 4) Create a 'Pair' C struct with two ids in it. Use it like the custom struct in (2). This struct is more reusable than the one in (2), so this solution seems less 'heavyweight', but it is less descriptive. 5) Define a 'Pair' Obj-C class with 'first' and 'second' properties, use as (3). Again, more reusable, less 'heavy' seeming than (3), but less descriptive. 6) Return an NSArray with two items in it (this seems the least descriptive option, from the point of view of someone reading the header). 7) Return an NSDictionary with two items in it, keyed by their property names. This seems a bit wasteful, since the dynamicisim of a dictionary is not required, and is also not so descriptive from a header-reading perspective. Oh, and there's also 8) Rename the file .mm, and use a C++ std::pair<id, id> class. (Only joking :-) How would you do this? Are there other, better options? Jamie. .com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
