-type State = "Dead" | "Alive";
+"use strict";
-type States = Array<State>;
+type GridLocation = {r: number, k: number};
-type Board = Array<States>;
-
-let state_of_integer = (i : number) : State => {
- switch (i)
- { case 0 : return "Dead"
- ; case 1 : return "Alive"
- }
+interface GridInterface<A> {
+ get : (location: GridLocation) => A;
+ map : (f : (location: GridLocation) => A) => void;
+ moore_neighbors: (origin : GridLocation) => Array<GridLocation>;
+ print : (toString : (A: A) => string) => void;
};
-let state_to_string = (state) : string => {
- switch (state)
- { case "Dead" : return " "
- ; case "Alive": return "o"
- }
-};
+class Grid<A> implements GridInterface<A> {
+ private rows : number;
+ private columns : number;
+ private cells : Array<Array<A>>;
-let board_new = ({rows, columns} : {rows: number, columns: number}) : Board => {
- let b = [];
- for (let r = 0; r < rows; r++) {
- b[r] = [];
- for (let k = 0; k < columns; k++) {
- let zero_or_one = Math.round(Math.random());
- b[r][k] = state_of_integer(zero_or_one);
+ constructor(
+ {rows, columns, init} :
+ { rows : number
+ , columns : number
+ , init : (location: GridLocation) => A
+ }
+ )
+ {
+ this.rows = rows;
+ this.columns = columns;
+ const cells = [];
+ for (let r = 0; r < rows; r++) {
+ cells[r] = [];
+ for (let k = 0; k < columns; k++) {
+ cells[r][k] = init({r: r, k: k})
+ };
};
+ this.cells = cells
+ };
+
+ get({r, k}: GridLocation) : A {
+ return this.cells[r][k]
+ };
+
+ moore_neighbors(origin : GridLocation) : Array<GridLocation> {
+ const offsets =
+ [ {r: -1, k: -1}, {r: -1, k: 0}, {r: -1, k: 1}
+ , {r: 0, k: -1}, {r: 0, k: 1}
+ , {r: 1, k: -1}, {r: 1, k: 0}, {r: 1, k: 1}
+ ];
+ const offset_to_location =
+ (offset) => {return {r: origin.r + offset.r, k: origin.k + offset.k}};
+ const locations = offsets.map(offset_to_location);
+ const is_location_within_bounds =
+ ({r, k}) => r >= 0 && k >= 0 && r < this.rows && k < this.columns;
+ return locations.filter(is_location_within_bounds)
};
- return b
-};
-let board_neighbors = (b : Board, origin : {r: number, k: number}) : States => {
- let rows = b.length;
- let cols = b[0].length;
- let offsets =
- [ {r: -1, k: -1}, {r: -1, k: 0}, {r: -1, k: 1}
- , {r: 0, k: -1}, {r: 0, k: 1}
- , {r: 1, k: -1}, {r: 1, k: 0}, {r: 1, k: 1}
- ];
- let offset_to_location =
- (offset) => {return {r: origin.r + offset.r, k: origin.k + offset.k}};
- let locations = offsets.map(offset_to_location);
- let is_location_within_bounds =
- ({r, k}) => {
- return r >= 0 && k >= 0 && r < rows && k < cols
+ map(f : (location: GridLocation) => A) {
+ this.cells =
+ this.cells.map((row, r) => row.map((_, k) => f({r: r, k: k})));
+ };
+
+ private print_border(): void {
+ process.stdout.write("+");
+ for (let k = 0; k < this.columns; k++) {
+ process.stdout.write("-");
};
- let locations_within_bounds = locations.filter(is_location_within_bounds);
- return locations_within_bounds.map(({r, k}) => b[r][k]);
-};
+ process.stdout.write("+");
+ process.stdout.write("\n");
+ };
-let state_is_alive = (s : State) : boolean => {
- if (s === "Alive") {return true} else if (s === "Dead") {return false}
+ print(to_string) : void {
+ this.print_border();
+ for (let r = 0; r < this.rows; r++) {
+ process.stdout.write("|");
+ for (let k = 0; k < this.columns; k++) {
+ const element = this.cells[r][k];
+ const element_string = to_string(element);
+ process.stdout.write(element_string);
+ };
+ process.stdout.write("|");
+ process.stdout.write("\n");
+ };
+ this.print_border();
+ };
};
-let state_next = (state : State, neighbor_states : Array<State>) : State => {
- let neighbors_alive = neighbor_states.filter(state_is_alive).length;
- if (state === "Alive" && neighbors_alive < 2) {
- return "Dead"
- } else if (state === "Alive" && neighbors_alive < 4) {
- return "Alive"
- } else if (state === "Alive" && neighbors_alive > 3) {
- return "Dead"
- } else if (state === "Dead" && neighbors_alive === 3) {
- return "Alive"
- } else {
- return state
- }
-}
-
-let board_next = (b0 : Board) : Board => {
- let b1 = [];
- for (let r = 0; r < b0.length; r++) {
- b1[r] = [];
- for (let k = 0; k < b0[r].length; k++) {
- let neighbors = board_neighbors(b0, {r: r, k: k});
- let state_0 = b0[r][k];
- let state_1 = state_next(state_0, neighbors);
- b1[r][k] = state_1;
- }
+namespace Terminal {
+ export const clear = () : void => {
+ process.stdout.write("\x1B[2J");
};
- return b1
-};
-let board_print_border = (b : Board) : void => {
- process.stdout.write("+");
- for (let k = 0; k < b[0].length; k++) {
- process.stdout.write("-");
+ export const reset = () : void => {
+ process.stdout.write("\x1B[1;1H");
};
- process.stdout.write("+");
- process.stdout.write("\n");
};
-let board_print = (b : Board) : void => {
- board_print_border(b);
- let rows = b.length;
- let columns = b[0].length;
- for (let r = 0; r < rows; r++) {
- process.stdout.write("|");
- for (let k = 0; k < columns; k++) {
- let state = b[r][k];
- let state_string = state_to_string(state);
- process.stdout.write(state_string);
+namespace Life {
+ namespace State {
+ export type T = "Dead" | "Alive";
+
+ export const of_integer = (i : number) : T => {
+ switch (i)
+ { case 0 : return "Dead"
+ ; case 1 : return "Alive"
+ ; default: throw new RangeError("No known State for integer: " + i)
+ }
+ };
+
+ export const to_string = (t : T) : string => {
+ switch (t)
+ { case "Dead" : return " "
+ ; case "Alive": return "o"
+ ; default : throw new TypeError("Illegal member of Life.State.T: " + t)
+ }
+ };
+
+ export const is_alive = (t : T) : boolean => {
+ switch (t)
+ { case "Dead" : return false
+ ; case "Alive": return true
+ ; default : throw new TypeError("Illegal member of Life.State.T: " + t)
+ }
+ };
+
+ export const next = (t : T, neighbors_alive : number) : T => {
+ const is_cell_alive = is_alive(t);
+ if (is_cell_alive && neighbors_alive < 2) {
+ return "Dead"
+ } else if (is_cell_alive && neighbors_alive < 4) {
+ return "Alive"
+ } else if (is_cell_alive && neighbors_alive > 3) {
+ return "Dead"
+ } else if (!is_cell_alive && neighbors_alive === 3) {
+ return "Alive"
+ } else {
+ return t
+ }
};
- process.stdout.write("|");
- process.stdout.write("\n");
};
- board_print_border(b);
-};
-let console_clear = () : void => {
- process.stdout.write("\033[2J");
-}
+ export class Board {
+ private grid: Grid<State.T>;
+
+ constructor(
+ {rows, columns} :
+ { rows : number
+ , columns : number
+ }
+ )
+ {
+ const init = (_) => State.of_integer(Math.round(Math.random()));
+ this.grid = new Grid({rows: rows, columns: columns, init: init});
+ };
+
+ next() : void {
+ this.grid.map(
+ (location) => {
+ const neighbor_locations = this.grid.moore_neighbors(location);
+ const neighbor_states = neighbor_locations.map((l) => this.grid.get(l));
+ const state_0 = this.grid.get(location);
+ const neighbors_alive = neighbor_states.filter(State.is_alive).length;
+ const state_1 = State.next(state_0, neighbors_alive);
+ return state_1
+ }
+ );
+ };
-let console_reset = () : void => {
- process.stdout.write("\033[1;1H");
-}
+ print() : void {
+ this.grid.print(State.to_string)
+ };
+ };
+};
-let board_loop = (b0 : Board) : void => {
- console_reset();
- board_print(b0);
- let b1 = board_next(b0);
- setTimeout(() => board_loop(b1), 250)
+const board_loop = (b : Life.Board) : void => {
+ Terminal.reset();
+ b.print();
+ b.next();
+ setTimeout(() => board_loop(b), 250)
};
-let main = () : void => {
- let height = parseInt(process.argv[2])
- let width = parseInt(process.argv[3])
- let b = board_new({rows: height - 3, columns: width - 2});
- console_clear();
+const main = () : void => {
+ const height = parseInt(process.argv[2])
+ const width = parseInt(process.argv[3])
+ const b = new Life.Board({rows: height - 3, columns: width - 2});
+ Terminal.clear();
board_loop(b);
};
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