-- Array Grid Example

-- Demonstrates using arrays for 2D grid operations (game use case)

-- Uses flat array with row-major indexing for O(1) cell access

module examples/runnable/array_grid

import std/io (print)

import std/array as A

-- Grid dimensions

let WIDTH = 5

let HEIGHT = 3

-- Helper: get index from (x, y) coordinates

pure func idx(x: int, y: int) -> int {

y * WIDTH + x

}

-- Get cell value

pure func getCell(grid: Array[int], x: int, y: int) -> int {

A.get(grid, idx(x, y))

}

-- Set cell value (returns new grid)

pure func setCell(grid: Array[int], x: int, y: int, value: int) -> Array[int] {

A.set(grid, idx(x, y), value)

}

-- Print row helper

pure func rowToString(grid: Array[int], y: int, x: int) -> string {

if x >= WIDTH then ""

else "${show(getCell(grid, x, y))} ${rowToString(grid, y, x + 1)}"

}

export func main() -> () ! {IO} =

-- Create a grid (flat array of size WIDTH * HEIGHT)

let emptyGrid = A.make(WIDTH * HEIGHT, 0) in

-- Create a sample grid with some values

let grid1 = setCell(emptyGrid, 0, 0, 1) in

let grid2 = setCell(grid1, 2, 1, 5) in

let grid3 = setCell(grid2, 4, 2, 9) in

-- Read some cells

let topLeft = getCell(grid3, 0, 0) in

let middle = getCell(grid3, 2, 1) in

let bottomRight = getCell(grid3, 4, 2) in

let empty = getCell(grid3, 1, 1) in

{

print("=== 2D Grid Example ===");

print("Grid size: ${show(WIDTH)}x${show(HEIGHT)}");

print("");

print("=== Cell Values ===");

print("Top-left (0,0): ${show(topLeft)}");

print("Middle (2,1): ${show(middle)}");

print("Bottom-right (4,2): ${show(bottomRight)}");

print("Empty cell (1,1): ${show(empty)}");

print("");

print("=== Grid Layout ===");

print("Row 0: ${rowToString(grid3, 0, 0)}");

print("Row 1: ${rowToString(grid3, 1, 0)}");

print("Row 2: ${rowToString(grid3, 2, 0)}")

}