This will help you understand that code better:
import strformat, typetraits
let r = [0 .. 3, 0 .. 3]
echo fmt"r = {r}, of type `{$r.type}'"
for x, y in r:
echo fmt"x = {x}, of type `{$x.type}'"
echo fmt"y = {y}, of type `{$y.type}'"
Run
Output:
r = [(a: 0, b: 3), (a: 0, b: 3)], of type `array[0..1, HSlice[system.int,
system.int]]'
x = 0, of type `range 0..1(int)'
y = (a: 0, b: 3), of type `HSlice[system.int, system.int]'
x = 1, of type `range 0..1(int)'
y = (a: 0, b: 3), of type `HSlice[system.int, system.int]'
Run
This is probably what you wanted:
import strformat, typetraits
for x in 0 .. 3:
for y in 0 .. 3:
echo fmt"x = {x}, of type `{$x.type}', y = {y}, of type `{$y.type}'"
Run
Outputs:
x = 0, of type `int', y = 0, of type `int'
x = 0, of type `int', y = 1, of type `int'
x = 0, of type `int', y = 2, of type `int'
x = 0, of type `int', y = 3, of type `int'
x = 1, of type `int', y = 0, of type `int'
x = 1, of type `int', y = 1, of type `int'
x = 1, of type `int', y = 2, of type `int'
x = 1, of type `int', y = 3, of type `int'
x = 2, of type `int', y = 0, of type `int'
x = 2, of type `int', y = 1, of type `int'
x = 2, of type `int', y = 2, of type `int'
x = 2, of type `int', y = 3, of type `int'
x = 3, of type `int', y = 0, of type `int'
x = 3, of type `int', y = 1, of type `int'
x = 3, of type `int', y = 2, of type `int'
x = 3, of type `int', y = 3, of type `int'
Run
