the other answer is on the money, but, in this particular case, it seems to me that you might want to have a function that could take both of those, with the idea that you never get more than max_num_items, but that if you find max_iter_id before that, the sequence stops there.
in that case, named args would be more suitable. something like function getitems(; max_num_items=-1, max_iter_id=...) where you might still have a special type for item id, but also have a special singleton that means "none" (like -1 means unlimited for max_num_items). then you could specify none (all items), either, or both. andrew On Friday, 26 June 2015 23:30:45 UTC-3, ks wrote: > > Hello everyone, > > I've just started to write a bit of code in Julia and I'm still exploring > the best ways of doing this and that. I'm having this small problem now and > wanted to ask for your advice. > > I'd like to have two methods that retrieve some items. The first method > takes the max number of items that should be retrieved. And the second > method takes the max item id. > > getitems( maxnumitems ) > getitems( maxitemid ) > > In both cases the argument has the same type: Int. So how do I take the > advantage of multiple dispatch mechanism in this situation? And is multiple > dispatch really the recommended way of handling a situation like this one? > Here're some alternatives that I thought of: > > 1. Use different function names: getitems, getitems_maxid. Not too elegant > as you mix purpose and details of function usage in its name. > 2. Use named arguments. This will cause the function implementation to > grow (a series of if / else), again not too elegant. > 3. Define a new type: ItemId which behaves exactly as Int but can be used > to 'activate' multiple dispatch (one function would use Int and the second > one would use ItemId). Generally not the best approach if you have methods > each having an argument that should be really represented as an Int rather > than a new type. > 4. ...? > > What would you recommend ? > > Thank you, > ks >
