If you keep reading from the link you gave:
The variable relation is declared inside the if block, but used outside.
However, when depending on this behavior, make sure all possible code paths
define a value for the variable. The following change to the above function
results in a runtime error
julia> function test(x,y)
if x < y
relation = "less than"
elseif x == y
relation = "equal to"
end
println("x is ", relation, " y.")
endtest (generic function with 1 method)
julia> test(1,2)x is less than y.
julia> test(2,1)ERROR: UndefVarError: relation not defined
in test at none:7
You will see that when i==2 you won't define x and therefore you will get
the runtime error.
On Monday, February 8, 2016 at 5:41:40 AM UTC-6, David van Leeuwen wrote:
>
> Hello,
>
> According to
> http://docs.julialang.org/en/release-0.4/manual/control-flow/#man-conditional-evaluation
> variables
> in if blocks do not introduce lexical scope, and hence are available
> afterwards. This makes sense and is what I need.
>
> However, it seems afterwards relates to position in the encapsulating
> block, and not to execution time.
>
> function testif()
> for i in 1:2
> if i==1
> x = 0
> end
> if x==2
> println(x)
> end
> end
> end
>
>
> This code gives me an undefined `x` in the print statement, where I would
> have expected `x` to be initialized in the first iteration. It seems I
> need to define `x` outside the for loop, even though I don't need it there.
>
>
> Is this interpretation in Julia intentional?
>
> Cheers,
>
> ---david
>
>
