for expression

The for expression allows one to do something with each item of a collection. It has a few different forms.

Iteration form

The iteration form allows one to do something with each item of a collection, in its defined order. It has the following syntax:

let A = [1, 2, 3];

for Item in A do
  A + 1;
end

Which will produce:

[2, 3, 4]

The Item part is a variable name that will refer to each item of the collection in turn.

Filter form

The filter form allows one to exclude items from the iteration. It has the following syntax:

let A = [3, 6, 9];

for Item in A if Item > 5 do
  Item + 1;
end

Which will produce:

[7, 10]

Nested form

The nested form allows one to do combine the iterations of different collections. It has the following syntax:

let A = [1, 2];
let B = ["a", "b"];

for Outer in A,
    Inner in B
do
  [Outer, Inner]
end

Which will produce:

[
  [1, "a"],
  [1, "b"],
  [2, "a"],
  [2, "b"]
]