go: implement improvements from rust

go/build.sh

@@ -7,7 +7,7 @@ DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
 source "$DIR/../common.sh"
 
 # Define project version here, normally would use git tags for this...
-PROJECT_VERSION="1.4.0"
+PROJECT_VERSION="1.5.0"
 
 USAGE="Usage: $(basename "$0") [OPTIONS]
 

go/othello/board.go

@@ -10,9 +10,10 @@ package othello
 import (
 	"errors"
 	"fmt"
+	"sort"
+
 	mapset "github.com/deckarep/golang-set/v2"
 	"github.com/logrusorgru/aurora/v4"
-	"sort"
 )
 
 // Board Handles game board state and logic.
@@ -98,11 +99,11 @@ func (b *Board) PlaceDisk(playerMove *Move) {
 	}
 	b.setSquare(&start, playerMove.Disk)
 	b.emptySquares.Remove(start)
-	for _, step := range playerMove.Directions {
-		pos := start.Add(step)
-		for b.getSquare(&pos) == playerMove.Disk.Opponent() {
+	for _, direction := range playerMove.Directions {
+		pos := start.Add(direction.Step)
+		for i := 0; i < direction.Count; i++ {
 			b.setSquare(&pos, playerMove.Disk)
-			pos = pos.Add(step)
+			pos = pos.Add(direction.Step)
 		}
 	}
 }
@@ -113,7 +114,7 @@ func (b *Board) PossibleMoves(disk Disk) []Move {
 	opposingDisk := disk.Opponent()
 	for square := range b.emptySquares.Iter() {
 		var value int
-		var directions []Step
+		var directions []StepCount
 		for _, step := range b.directions {
 			pos := square.Add(step)
 			// Next square in this direction needs to be the opposing disk
@@ -128,7 +129,7 @@ func (b *Board) PossibleMoves(disk Disk) []Move {
 			// Valid move only if a line of opposing disks ends in own disk
 			if b.getSquare(&pos) == disk {
 				value += numSteps
-				directions = append(directions, step)
+				directions = append(directions, StepCount{step, numSteps})
 			}
 		}
 		if value > 0 {
@@ -156,7 +157,7 @@ func (b *Board) printPossibleMoves(moves []Move) {
 	}
 	// Add possible moves to board
 	for _, possibleMove := range moves {
-		index := possibleMove.Square.Y*b.size + possibleMove.Square.X
+		index := b.squareIndex(&possibleMove.Square)
 		formattedBoard[index] = aurora.Yellow(fmt.Sprintf("%d", possibleMove.Value)).String()
 		fmt.Printf("  %s\n", possibleMove)
 	}
@@ -219,13 +220,19 @@ func (b *Board) get(x, y int) (Disk, error) {
 // Returns the state of the board (empty, white, black) at the given square.
 func (b *Board) getSquare(square *Square) Disk {
 	if b.checkCoordinates(square.X, square.Y) {
-		return b.board[square.Y*b.size+square.X]
+		index := b.squareIndex(square)
+		return b.board[index]
 	}
 	// Square is out of bounds.
 	// This probably should return a (Disk, error) instead but that makes using this quite cumbersome...
 	return Empty
 }
 
+// Get all the squares playing this move will change
+func (b *Board) squareIndex(square *Square) int {
+	return square.Y*b.size + square.X
+}
+
 // Count and return the number of black and white disks.
 func (b *Board) playerScores() (int, int) {
 	var black, white int
@@ -255,7 +262,8 @@ func (b *Board) setSquare(square *Square, disk Disk) {
 	if !b.checkCoordinates(square.X, square.Y) {
 		panic("Invalid coordinates")
 	}
-	b.board[square.Y*b.size+square.X] = disk
+	index := b.squareIndex(square)
+	b.board[index] = disk
 }
 
 // Format game board to string

go/othello/player.go

@@ -9,9 +9,10 @@ package othello
 
 import (
 	"fmt"
-	"github.com/logrusorgru/aurora/v4"
 	"math/rand"
 	"time"
+
+	"github.com/logrusorgru/aurora/v4"
 )
 
 // Player Defines one player (human or computer).

go/othello/utils.go

@@ -12,8 +12,10 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
-	"github.com/logrusorgru/aurora/v4"
 	"runtime/debug"
+	"sort"
+
+	"github.com/logrusorgru/aurora/v4"
 )
 
 // Set at build time
@@ -52,7 +54,16 @@ type Move struct {
 	Square     Square
 	Disk       Disk
 	Value      int
-	Directions []Step
+	Directions []StepCount
+}
+
+// Squares implements sort.Interface for a slice of Square objects
+type Squares []Square
+
+// Hold Step and number of steps since Go lacks a tuple / pair construct
+type StepCount struct {
+	Step  Step
+	Count int
 }
 
 // MovesDescending implements sort.Interface with custom sort order.
@@ -121,6 +132,10 @@ func (m MovesDescending) Less(i, j int) bool {
 	return false
 }
 
+func (s Squares) Len() int           { return len(s) }
+func (s Squares) Less(i, j int) bool { return s[i].IsLessThan(s[j]) }
+func (s Squares) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
 // BoardChar Returns a single character identifier string for the given disk.
 func (d Disk) BoardChar() string {
 	switch d {
@@ -197,6 +212,20 @@ func (m Move) LogEntry() string {
 	return fmt.Sprintf("%s:%s,%d", m.Disk.BoardChar(), m.Square, m.Value)
 }
 
+// Get all the squares playing this move will change
+func (m Move) AffectedSquares() []Square {
+	var paths Squares
+	for _, direction := range m.Directions {
+		pos := m.Square.Add(direction.Step)
+		for i := 0; i < int(direction.Count); i++ {
+			paths = append(paths, pos)
+			pos = pos.Add(direction.Step)
+		}
+	}
+	sort.Sort(paths)
+	return paths
+}
+
 // Calculate SHA256 hash for the given string.
 func calculateSHA256(input string) string {
 	data := []byte(input)