Local is better then global!

This is one of our rules. But this rule is somehow in contradiction with the rule: "Explicit is better than implicit" when we are talking about _scan_ and _control variable_ iterator. In the next example variable i is explicit declared.

Plan: A

make i ∈ Z; -- local variable
scan [0..10] :> i do
  ** force next iteration
  when i % 2 = 0 do
    skip;
  else
    ** write only odd numbers
    write i;
    write ',' if (i < 10);
  done;
next;
print i; -- still available

​

The question for debate is: Should we implicit declare i using ∈ in the scan context ? Like:

Plan: B

```
scan i ∈ (0..10:2) do
  ** write only odd numbers
  write i;
  write ',' if (i < 10);
next;
print i; -- unavailable
```

Which one is better?