module main

struct IntList {
mut:
    values []int
}

fn (l IntList) [] (index int) int {
    return l.values[index]
}

fn (mut l IntList) []= (index int, value int) {
    l.values[index] = value
}

struct Tensor {
mut:
    last_set       int
    last_signature int
}

fn (t Tensor) [] (parts []SliceIndex) int {
    mut total := 0
    for part in parts {
        if part.is_range {
            total += 100
            if part.has_low {
                total += part.low * 10
            }
            if part.has_high {
                total += part.high
            }
        } else {
            total += part.value
        }
    }
    return total
}

fn (mut t Tensor) []= (parts []SliceIndex, value int) {
    mut total := 0
    for part in parts {
        if part.is_range {
            total += 100
            if part.has_low {
                total += part.low * 10
            }
            if part.has_high {
                total += part.high
            }
        } else {
            total += part.value
        }
    }
    t.last_signature = total
    t.last_set = value
}

struct Axis {}

fn (a Axis) [] (part SliceIndex) int {
    if part.is_range {
        mut total := 100
        if part.has_low {
            total += part.low * 10
        }
        if part.has_high {
            total += part.high
        }
        return total
    }
    return part.value
}

fn test_operator_overloading_index() {
    mut list := IntList{
        values: [3, 5, 8]
    }
    assert list[1] == 5
    list[1] = 33
    assert list[1] == 33
    list[1] += 7
    assert list[1] == 40
    list[0] *= 4
    assert list[0] == 12
}

fn test_operator_overloading_multi_index() {
    mut tensor := Tensor{}
    assert tensor[1, 2] == 3
    assert tensor[1..3, .., 4..] == 353
    tensor[2, ..3] = 7
    assert tensor.last_signature == 105
    assert tensor.last_set == 7
    tensor[1, 3..] += 1
    assert tensor.last_signature == 131
    assert tensor.last_set == 132

    axis := Axis{}
    assert axis[2] == 2
    assert axis[..3] == 103
    assert axis[4..] == 140
}