[julia-users] Newbie question about Tasks

[Bill Allen]

To learn julia, I'm working my way through Project Euler 
<https://projecteuler.net/>. For question #2, 
<https://projecteuler.net/problem=2> I ran into an issue that I haven't 
found a solution to.

Given a function that computes fibonacci numbers:

function fib(n)
       a,b = 0,1
       while(a < n)
           produce(a)
           a,b=b,a+b
       end
end

I can write a loop that computes the value:

function fibsum(n)
           s = 0
           for x in Task(() -> fib(n))
               if x % 2 == 0 
                   s = s + x 
               end
           end
           s
end

fibsum(4000000)
4613732

Analogously, one can write:

s = 0
for x in [1,2,3] 
    s = s + x
end
println(s)
6

or more succinctly,

sum([x for x in [1,2,3]])

But, when I try that with the fib Task:

sum([x for x in Task(()->fib(10))])

I get 

ERROR: `length` has no method matching length(::Task)
 in anonymous at no file

Which confuses me sense the task works nicely in an explicit loop.

Regards,
Bill