[coldtea]

>The only real cases I can see is creating new data structures

Half of programming is creating new data structures.

The other half is tranformations (e.g. map, filter, reduce, min, max, etc) which also benefit from being generic.

[lkramer]

Sorry, when I said new data structures, I meant containers like maps and list, which I very rarely get to create day to day.

I can see it for your transformations, but I have seldom seen cases where generics would really help (usually we're talking about comparing complex structure types that will need custom code anyway).

[Smaug123]

"Theorems for free"! By which I mean, when I'm coding something and it could be universally quantified on the type, then it's better to do so. That way, it's impossible to phrase certain errors. For example, a function `Set<a> -> Set<a>` must produce a subset of the input set; that's guaranteed by the types. I can't accidentally include the value 0 in my set, because 0 isn't of that generic type. The generic forces you to think in terms of the structure you're manipulating, rather than in terms of its contents.

[esarbe]

How about sets?