Re: The meaning of 'sugar' [Forked from Re: Why do we have ipairs?]

[Coda Highland <chighland@...>]

On Thu, Jun 12, 2014 at 7:12 PM, Rena <hyperhacker@gmail.com> wrote:
> On Wed, Jun 11, 2014 at 10:13 PM, Ross Bencina <rossb-lists@audiomulch.com>
> wrote:
>>
>> The problem is in Lua (unless I'm missing something), you don't have
>> symbolic constants, so it's not possible to "compile" the second form to
>> anything better than a sequence of comparisons. If you use Lua variables,
>> their values are not constant, and so could change each time the switch is
>> executed (hence the equivalence to a linear if/else chain).
>
>
> Well, Lua *does* have constants:
>
> switch event.type
>   case 'move' print("I was moved to", event.x, event.y) break
>   case 'resize' print("I was resized to", event.w, event.h) break
>   case else print("I don't know how to deal with", event.type)
> end
>

And thanks to string interning, these are as fast as integer comparisons.

/s/ Adam