2.wsf

# Advent of Code 2021
# Day 2: Dive!
# https://adventofcode.com/2021/day/2

    "@string" import

    # 0    x
    # 1    y (part 1), aim (part 2)
    # 2    y (part 2)
    # 3    read temp
    # 4-15 command constants
    # 16+  command

    -1 "forwardownup" 4 call string.store_neg

    3 ^ readi retrieve
.loop:
    1-
    ^ jn .end
    16 ' ' call string.read_until
    3 ^ readi retrieve
    16 ^2 4  7 call string.equals 1 j= .move_forward
    16 ^2 10 4 call string.equals 1 j= .move_down
    16 ^2 14 2 call string.equals 1 j= .move_up
    drop
    -1 "Invalid command: " call string.print_neg_stack
    16 swap call string.println
    drop end
.end:
    drop
    0 retrieve 1 retrieve * printi '\n' printc # x * aim
    0 retrieve 2 retrieve * printi '\n' printc # x * y
    end

.move_forward:
    0 ^ retrieve ^2 + store # x += n
    2 ^ retrieve 1 retrieve ^3 * + store # y += aim*n
    2drop jmp .loop
.move_up:
    neg # n *= -1
.move_down:
    1 ^ retrieve ^2 + store # aim += n
    2drop jmp .loop