Re: The meaning of 'sugar' [Forked from Re: Why do we have ipairs?]
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- Subject: Re: The meaning of 'sugar' [Forked from Re: Why do we have ipairs?]
- From: Coda Highland <chighland@...>
- Date: 2014年6月13日 11:42:00 -0700
On Fri, Jun 13, 2014 at 11:32 AM, Tomas Guisasola Gorham
<tomas@tecgraf.puc-rio.br> wrote:
> I don't need switch:
>
> local event_handler = {
> MOUSECLICK = function (...) ... end,
> KEYPRESS = function (...) ... end,
> ...
> }
> ...
> local callback = event_handler[x]
> if callback then
> callback(...)
> end
>
> Don't you use that kind of construction?
>
> Regards,
> Tomás
Yes, this was brought up earlier in the thread. :P But in this case, x
is a string, not a number. (Which was ALSO brought up in this thread
already.)
Splitting the difference:
MOUSECLICK = 43
KEYPRESS = 67
local event_handler = {
[MOUSECLICK] = function(...) ... end,
[KEYPRESS] = function(...) ... end
}
local callback = event_handler[x]
...
So assuming that your backend is returning numeric constants instead
of string labels, you can use something like this. But that's not the
same use case; that's defining independent functions that have a
central dispatch location, rather than defining a set of snippets that
all need to conditionally execute in the same context.
/s/ Adam