Re: Strange Operators (Was: Why I leave Lua)

[William Ahern <william@...>]

On Wed, Jul 09, 2014 at 05:09:42PM -0700, Coroutines wrote:
> On Wed, Jul 9, 2014 at 5:05 PM, Coroutines <coroutines@gmail.com> wrote:
> 
> > The spaceship operator is my favorite ("<=>"):
> > https://en.wikipedia.org/wiki/Spaceship_operator
> 
> Another fun one is the NULL coalescing operator found in some languages.
> 
> In Lua you handle default args like:
> 
> if default_arg then
>     default_arg = 3
> end
> 
> -- or
> 
> default_arg = default_arg or 3
> 
> (let's pretend I'm comparing against nil for best practices)
> 
> Anyway, C# has "??" to do that: default_arg = default_arg ?? 3;
> 
> https://en.wikipedia.org/wiki/Null_coalescing_operator

GCC C has ?:

	z = x?:y;

It's just a hack on the ternary operator, but behaves precisely the same way
in that x will only be evaluated once. GCC has supported this since at least
2.95, circa 1999.