From 7a1ca2516c8f67fb47fda6420967d6549d87f307 Mon Sep 17 00:00:00 2001
From: Arek <ar@ar76.eu>
Date: Sat, 15 Mar 2025 11:40:08 +0100
Subject: [PATCH] chore: incorporate range over integers syntax

---
 gol/arena.go | 81 +++++++++++++++++++++++++++++++++++++++++++
 gol/types.go | 98 ----------------------------------------------------
 2 files changed, 81 insertions(+), 98 deletions(-)
 create mode 100644 gol/arena.go
 delete mode 100644 gol/types.go

diff --git a/gol/arena.go b/gol/arena.go
new file mode 100644
index 0000000..1219001
--- /dev/null
+++ b/gol/arena.go
@@ -0,0 +1,81 @@
+package gol
+
+import (
+	"bytes"
+	"os"
+	"sync"
+)
+
+type Arena [][]bool
+
+func New(ysize, xsize int) Arena {
+	var arena = make([][]bool, ysize)
+	for i := range ysize {
+		arena[i] = make([]bool, xsize)
+	}
+	return arena
+}
+
+// bufPool
+var bufPool = sync.Pool{
+	New: func() any {
+		return new(bytes.Buffer)
+	},
+}
+
+var (
+	spriteOn  = ([]byte)("\ue0b6\ue0b4")
+	spriteOff = ([]byte)("\u2022\u2022")
+)
+
+func (a Arena) PrintMe() {
+	b := bufPool.Get().(*bytes.Buffer)
+	b.Reset()
+
+	for i := range len(a) {
+		for j := range len(a[0]) {
+			if a[i][j] {
+				b.Write(spriteOn)
+			} else {
+				b.Write(spriteOff)
+			}
+		}
+		b.WriteRune('\n')
+	}
+	os.Stdout.Write(b.Bytes())
+	bufPool.Put(b)
+}
+
+func (a Arena) NextGen(to Arena) {
+	for y := range len(a) {
+		for x := range len(a[0]) {
+			to[y][x] = a.life(x, y)
+		}
+	}
+}
+
+func (a Arena) life(x, y int) bool {
+	neighbours := a.countNeighbours(x, y)
+	iAmAlive := a[y][x]
+	return neighbours == 3 || (iAmAlive && neighbours == 2)
+}
+
+func (a Arena) countNeighbours(x, y int) int {
+	ysize := len(a)
+	xsize := len(a[0])
+
+	count := 0
+	for dy := -1; dy <= 1; dy++ {
+		for dx := -1; dx <= 1; dx++ {
+			if dx == 0 && dy == 0 {
+				continue
+			}
+			ny := (y + dy + ysize) % ysize
+			nx := (x + dx + xsize) % xsize
+			if a[ny][nx] {
+				count++
+			}
+		}
+	}
+	return count
+}
diff --git a/gol/types.go b/gol/types.go
deleted file mode 100644
index 0c58b08..0000000
--- a/gol/types.go
+++ /dev/null
@@ -1,98 +0,0 @@
-package gol
-
-import (
-	"bytes"
-	"os"
-	"sync"
-)
-
-type Arena [][]bool
-
-func New(ysize, xsize int) Arena {
-	var arena = make([][]bool, ysize)
-	for i := 0; i < ysize; i++ {
-		arena[i] = make([]bool, xsize)
-	}
-	return arena
-}
-
-// bufPool
-var bufPool = sync.Pool{
-	New: func() any {
-		return new(bytes.Buffer)
-	},
-}
-
-func (a Arena) PrintMe() {
-	b := bufPool.Get().(*bytes.Buffer)
-	b.Reset()
-	spriteOn := ([]byte)("\ue0b6\ue0b4")
-	spriteOff := ([]byte)("\u2022\u2022")
-
-	for i := 0; i < len(a); i++ {
-		for j := 0; j < len(a[0]); j++ {
-			if a[i][j] {
-				b.Write(spriteOn)
-			} else {
-				b.Write(spriteOff)
-			}
-		}
-		b.WriteRune('\n')
-	}
-	os.Stdout.Write(b.Bytes())
-	bufPool.Put(b)
-}
-
-func (a Arena) NextGen(to Arena) {
-	for y := 0; y < len(a); y++ {
-		for x := 0; x < len(a[0]); x++ {
-			to[y][x] = a.Life(x, y)
-		}
-	}
-}
-
-func (a Arena) Life(x, y int) bool {
-	count := a.countN(x, y)
-	current := a[y][x]
-	if !current && count == 3 {
-		return true
-	}
-	if current && (count == 2 || count == 3) {
-		return true
-	}
-	return false
-}
-
-type pair struct {
-	x int
-	y int
-}
-
-func (a Arena) countN(x, y int) int {
-	ysize := len(a)
-	xsize := len(a[0])
-
-	xb := (x - 1 + xsize) % xsize
-	xa := (x + 1 + xsize) % xsize
-	yb := (y - 1 + ysize) % ysize
-	ya := (y + 1 + ysize) % ysize
-
-	neigh := [8]pair{
-		{xb, yb},
-		{x, yb},
-		{xa, yb},
-		{xb, y},
-		{xa, y},
-		{xb, ya},
-		{x, ya},
-		{xa, ya},
-	}
-
-	count := 0
-	for _, p := range neigh {
-		if a[p.y][p.x] {
-			count++
-		}
-	}
-	return count
-}