Generator Evaluation Order?

General Usage
1 
julia> fun() = begin
           res = 0
           map(tuple,
               begin
                       ret = ((a=1/(i+j);res+=a;println("VAL = ",res);a) for i=1:2, j=1:2)
                       println("RES : ",res)
                       ret
               end,
           [1 3; 2 4])
           res
       end
fun (generic function with 1 method)

julia> fun()
RES : 0
VAL = 0.5
VAL = 0.8333333333333333
VAL = 1.1666666666666665
VAL = 1.4166666666666665
1.4166666666666665

why later coming println statement is printed out first? Why is the evaluation order not preserved?

Thanks

2

ret = ... just defines the generator, it does not generate anything.

It’s the same reason you won’t get output after evaluating

f() = println("AAAA")
3

How do you generate from a generator? what function does map call to activate the generator?

Thanks

4

The generator expression returns something iteratable and you just iterate on it. You can manually call the iterator protocol or us anything that iterates an iterator.

5

Also, if you want to access the result before passing it to map somehow, you should just use a comprehension, which is just a collect on the generator.