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On 12/22/2014 06:58 PM, Antonio Scuri wrote:
> Hi,
>
> I would like to write something like this *in a single line*:
>
> y = (x == nil)? x: x + 1
>
> If I do this:
>
> y = testfunc(x == nil, x, x+1)
>
> and implement the "if" inside the function, I have the problem that
> both expressions are evaluated before calling the function, and the
> second _expression_ will produce an error when x is nil.
>
> I'm not seeing the solution. Is this possible?
>
> Thanks,
> Scuri
>
You can do this with 'and' and 'or' operators. What in C you'd write as
a ? b : c
in Lua you can write like
a and b or c
the only issue being that b cannot be false-y.
In your case, however, b is false-y, so you have to reorder your
statement as
x ~= nil and x + 1 or x
For more information regarding this problem see the respective page on
lua-users wiki: http://lua-users.org/wiki/TernaryOperator
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