Fix board iterators on square boards

1 files changed, 24 insertions, 3 deletions

diff --git a/bingo/board.go b/bingo/board.go
index 479623f..1c63592 100644
--- a/bingo/board.go
+++ b/bingo/board.go
@@ -1,6 +1,9 @@
 package bingo
 
-import "iter"
+import (
+	"fmt"
+	"iter"
+)
 
 type WinDirection int
 
@@ -27,6 +30,19 @@ func all(group []Tile) bool {
 	return allTrue
 }
 
+// create a new game of a given side length
+//
+// returns an error if side length is not odd
+func newGame(length int) (*Game, error) {
+	if length%2 != 1 || length < 3 {
+		return nil, fmt.Errorf("Invalid Side Length: %d", length)
+	}
+	game := new(Game)
+    game.Length = length
+
+	return game, nil
+}
+
 // Return if a game has been won
 func (g Game) Win() bool {
 	for row := range g.Rows() {
@@ -53,7 +69,7 @@ func (g Game) Win() bool {
 // Iterator for rows of a board
 func (g Game) Rows() iter.Seq[[]Tile] {
 	return func(yield func([]Tile) bool) {
-		for row := 0; (row+1)*g.Length > len(g.Board); row++ {
+		for row := 0; (row+1)*g.Length <= len(g.Board); row++ {
 			if !yield(g.Board[row*g.Length : (row+1)*g.Length]) {
 				return
 			}
@@ -64,7 +80,7 @@ func (g Game) Rows() iter.Seq[[]Tile] {
 // Iterator for columns of a board
 func (g Game) Cols() iter.Seq[[]Tile] {
 	return func(yield func([]Tile) bool) {
-		for col := 0; col*g.Length+1 > len(g.Board); col++ {
+		for col := 0; col*g.Length+1 < len(g.Board); col++ {
 			column := make([]Tile, g.Length)
 			for i := range g.Length {
 				column[i] = g.Board[i*g.Length+col]
@@ -77,6 +93,8 @@ func (g Game) Cols() iter.Seq[[]Tile] {
 }
 
 // Iterator for diagonals of square boards
+//
+// On non-square boards yields nothing
 func (g Game) Diags() iter.Seq[[]Tile] {
 	return func(yield func([]Tile) bool) {
 		if g.Length*g.Length != len(g.Board) {
@@ -94,5 +112,8 @@ func (g Game) Diags() iter.Seq[[]Tile] {
 		for i := 0; i < g.Length; i++ {
 			diagonal[i] = g.Board[i*g.Length+(g.Length-1-i)]
 		}
+		if !yield(diagonal) {
+			return
+		}
 	}
 }