Game of Life with Scala and Functional Programming
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I have been doing OOP and imperative programming my whole career but I wanted to dabble in Scala along with functional programming. Rather than writing Java like code in Scala I wanted to try a more functional approach. I decided to try a simple Kata with Scala, Game of Life. The following is what I came up with. I admit I am very much stuck in OOP/imperative mindset. I am not sure if this is the best approach for Scala, or functional programming. I avoided functions that mutate objects, and favor returning a new copy. I was unsure what the best approach is with functional programming to ensure objects can't be created in an invalid state. Is there a way I can make my code more aligned with idiomatic Scala and functional programming.
package io.jkratz.katas.gameoflife
import scala.util.Random
case class Board(grid: Array[Array[Int]]) {
require(grid != null, "grid cannot be null")
require(!isJagged(grid), "grid cannot be jagged")
require(isValid(grid), "grid contains invalid values, 0 and 1 are the only valid values")
val rows: Int = {
grid.length
}
val columns: Int = {
grid(0).length
}
def evolve(): Board = {
val newGrid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
newGrid(i)(j) = getNextCellState(i,j)
}
}
Board(newGrid)
}
private def getNextCellState(i:Int, j: Int): Int = {
var liveCount = 0
val cellValue = grid(i)(j)
for (x <- -1 to 1; y <- -1 to 1) {
if (i + x < 0 || i + x > (this.rows - 1) || y + j < 0 || y + j > (this.columns - 1)) {
// do nothing, out of bounds
} else {
liveCount += grid(i + x)(j + y)
}
}
liveCount -= cellValue
if (cellValue.equals(Board.CELL_ALIVE) && (liveCount < 2 || liveCount > 3)) {
Board.CELL_DEAD
} else if (cellValue.equals(Board.CELL_DEAD) && liveCount == 3) {
Board.CELL_ALIVE
} else {
cellValue
}
}
private def isJagged(grid: Array[Array[Int]]): Boolean = {
var valid = true
val size = grid(0).length
grid.foreach(row => if (row.length.equals(size)) valid = false)
valid
}
private def isValid(grid: Array[Array[Int]]): Boolean = {
var valid = true
for (i <- grid.indices; j <- grid(0).indices) {
val x = grid(i)(j)
if (x != 0 && x != 1) {
valid = false
}
}
valid
}
}
object Board {
val CELL_DEAD = 0
val CELL_ALIVE = 1
val DEFAULT_ROWS = 10
val DEFAULT_COLUMNS = 10
def random(rows: Int = DEFAULT_ROWS, columns: Int = DEFAULT_COLUMNS): Board = {
val grid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
grid(i)(j) = Random.nextInt(2)
}
}
Board(grid=grid)
}
def prettyPrint(board: Board): Unit = {
val grid = board.grid
for (i <- grid.indices) {
for (j <- grid(0).indices) {
if (grid(i)(j) == 0) print(" - ") else print(" * ")
}
println()
}
}
}
And my main entry point.
package io.jkratz.katas.gameoflife
object Life {
def main(args: Array[String]): Unit = {
val state0 = Board.random(5,5)
println("State 0")
Board.prettyPrint(state0)
val state1 = state0.evolve()
println("State 1")
Board.prettyPrint(state1)
}
}
functional-programming scala game-of-life
asked 2 hours ago
jkratz55
101
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jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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up vote
0
down vote
favorite
I have been doing OOP and imperative programming my whole career but I wanted to dabble in Scala along with functional programming. Rather than writing Java like code in Scala I wanted to try a more functional approach. I decided to try a simple Kata with Scala, Game of Life. The following is what I came up with. I admit I am very much stuck in OOP/imperative mindset. I am not sure if this is the best approach for Scala, or functional programming. I avoided functions that mutate objects, and favor returning a new copy. I was unsure what the best approach is with functional programming to ensure objects can't be created in an invalid state. Is there a way I can make my code more aligned with idiomatic Scala and functional programming.
package io.jkratz.katas.gameoflife
import scala.util.Random
case class Board(grid: Array[Array[Int]]) {
require(grid != null, "grid cannot be null")
require(!isJagged(grid), "grid cannot be jagged")
require(isValid(grid), "grid contains invalid values, 0 and 1 are the only valid values")
val rows: Int = {
grid.length
}
val columns: Int = {
grid(0).length
}
def evolve(): Board = {
val newGrid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
newGrid(i)(j) = getNextCellState(i,j)
}
}
Board(newGrid)
}
private def getNextCellState(i:Int, j: Int): Int = {
var liveCount = 0
val cellValue = grid(i)(j)
for (x <- -1 to 1; y <- -1 to 1) {
if (i + x < 0 || i + x > (this.rows - 1) || y + j < 0 || y + j > (this.columns - 1)) {
// do nothing, out of bounds
} else {
liveCount += grid(i + x)(j + y)
}
}
liveCount -= cellValue
if (cellValue.equals(Board.CELL_ALIVE) && (liveCount < 2 || liveCount > 3)) {
Board.CELL_DEAD
} else if (cellValue.equals(Board.CELL_DEAD) && liveCount == 3) {
Board.CELL_ALIVE
} else {
cellValue
}
}
private def isJagged(grid: Array[Array[Int]]): Boolean = {
var valid = true
val size = grid(0).length
grid.foreach(row => if (row.length.equals(size)) valid = false)
valid
}
private def isValid(grid: Array[Array[Int]]): Boolean = {
var valid = true
for (i <- grid.indices; j <- grid(0).indices) {
val x = grid(i)(j)
if (x != 0 && x != 1) {
valid = false
}
}
valid
}
}
object Board {
val CELL_DEAD = 0
val CELL_ALIVE = 1
val DEFAULT_ROWS = 10
val DEFAULT_COLUMNS = 10
def random(rows: Int = DEFAULT_ROWS, columns: Int = DEFAULT_COLUMNS): Board = {
val grid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
grid(i)(j) = Random.nextInt(2)
}
}
Board(grid=grid)
}
def prettyPrint(board: Board): Unit = {
val grid = board.grid
for (i <- grid.indices) {
for (j <- grid(0).indices) {
if (grid(i)(j) == 0) print(" - ") else print(" * ")
}
println()
}
}
}
And my main entry point.
package io.jkratz.katas.gameoflife
object Life {
def main(args: Array[String]): Unit = {
val state0 = Board.random(5,5)
println("State 0")
Board.prettyPrint(state0)
val state1 = state0.evolve()
println("State 1")
Board.prettyPrint(state1)
}
}
functional-programming scala game-of-life
asked 2 hours ago
jkratz55
101
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I have been doing OOP and imperative programming my whole career but I wanted to dabble in Scala along with functional programming. Rather than writing Java like code in Scala I wanted to try a more functional approach. I decided to try a simple Kata with Scala, Game of Life. The following is what I came up with. I admit I am very much stuck in OOP/imperative mindset. I am not sure if this is the best approach for Scala, or functional programming. I avoided functions that mutate objects, and favor returning a new copy. I was unsure what the best approach is with functional programming to ensure objects can't be created in an invalid state. Is there a way I can make my code more aligned with idiomatic Scala and functional programming.
package io.jkratz.katas.gameoflife
import scala.util.Random
case class Board(grid: Array[Array[Int]]) {
require(grid != null, "grid cannot be null")
require(!isJagged(grid), "grid cannot be jagged")
require(isValid(grid), "grid contains invalid values, 0 and 1 are the only valid values")
val rows: Int = {
grid.length
}
val columns: Int = {
grid(0).length
}
def evolve(): Board = {
val newGrid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
newGrid(i)(j) = getNextCellState(i,j)
}
}
Board(newGrid)
}
private def getNextCellState(i:Int, j: Int): Int = {
var liveCount = 0
val cellValue = grid(i)(j)
for (x <- -1 to 1; y <- -1 to 1) {
if (i + x < 0 || i + x > (this.rows - 1) || y + j < 0 || y + j > (this.columns - 1)) {
// do nothing, out of bounds
} else {
liveCount += grid(i + x)(j + y)
}
}
liveCount -= cellValue
if (cellValue.equals(Board.CELL_ALIVE) && (liveCount < 2 || liveCount > 3)) {
Board.CELL_DEAD
} else if (cellValue.equals(Board.CELL_DEAD) && liveCount == 3) {
Board.CELL_ALIVE
} else {
cellValue
}
}
private def isJagged(grid: Array[Array[Int]]): Boolean = {
var valid = true
val size = grid(0).length
grid.foreach(row => if (row.length.equals(size)) valid = false)
valid
}
private def isValid(grid: Array[Array[Int]]): Boolean = {
var valid = true
for (i <- grid.indices; j <- grid(0).indices) {
val x = grid(i)(j)
if (x != 0 && x != 1) {
valid = false
}
}
valid
}
}
object Board {
val CELL_DEAD = 0
val CELL_ALIVE = 1
val DEFAULT_ROWS = 10
val DEFAULT_COLUMNS = 10
def random(rows: Int = DEFAULT_ROWS, columns: Int = DEFAULT_COLUMNS): Board = {
val grid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
grid(i)(j) = Random.nextInt(2)
}
}
Board(grid=grid)
}
def prettyPrint(board: Board): Unit = {
val grid = board.grid
for (i <- grid.indices) {
for (j <- grid(0).indices) {
if (grid(i)(j) == 0) print(" - ") else print(" * ")
}
println()
}
}
}
And my main entry point.
package io.jkratz.katas.gameoflife
object Life {
def main(args: Array[String]): Unit = {
val state0 = Board.random(5,5)
println("State 0")
Board.prettyPrint(state0)
val state1 = state0.evolve()
println("State 1")
Board.prettyPrint(state1)
}
}
functional-programming scala game-of-life
asked 2 hours ago
jkratz55
101
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I have been doing OOP and imperative programming my whole career but I wanted to dabble in Scala along with functional programming. Rather than writing Java like code in Scala I wanted to try a more functional approach. I decided to try a simple Kata with Scala, Game of Life. The following is what I came up with. I admit I am very much stuck in OOP/imperative mindset. I am not sure if this is the best approach for Scala, or functional programming. I avoided functions that mutate objects, and favor returning a new copy. I was unsure what the best approach is with functional programming to ensure objects can't be created in an invalid state. Is there a way I can make my code more aligned with idiomatic Scala and functional programming.
package io.jkratz.katas.gameoflife
import scala.util.Random
case class Board(grid: Array[Array[Int]]) {
require(grid != null, "grid cannot be null")
require(!isJagged(grid), "grid cannot be jagged")
require(isValid(grid), "grid contains invalid values, 0 and 1 are the only valid values")
val rows: Int = {
grid.length
}
val columns: Int = {
grid(0).length
}
def evolve(): Board = {
val newGrid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
newGrid(i)(j) = getNextCellState(i,j)
}
}
Board(newGrid)
}
private def getNextCellState(i:Int, j: Int): Int = {
var liveCount = 0
val cellValue = grid(i)(j)
for (x <- -1 to 1; y <- -1 to 1) {
if (i + x < 0 || i + x > (this.rows - 1) || y + j < 0 || y + j > (this.columns - 1)) {
// do nothing, out of bounds
} else {
liveCount += grid(i + x)(j + y)
}
}
liveCount -= cellValue
if (cellValue.equals(Board.CELL_ALIVE) && (liveCount < 2 || liveCount > 3)) {
Board.CELL_DEAD
} else if (cellValue.equals(Board.CELL_DEAD) && liveCount == 3) {
Board.CELL_ALIVE
} else {
cellValue
}
}
private def isJagged(grid: Array[Array[Int]]): Boolean = {
var valid = true
val size = grid(0).length
grid.foreach(row => if (row.length.equals(size)) valid = false)
valid
}
private def isValid(grid: Array[Array[Int]]): Boolean = {
var valid = true
for (i <- grid.indices; j <- grid(0).indices) {
val x = grid(i)(j)
if (x != 0 && x != 1) {
valid = false
}
}
valid
}
}
object Board {
val CELL_DEAD = 0
val CELL_ALIVE = 1
val DEFAULT_ROWS = 10
val DEFAULT_COLUMNS = 10
def random(rows: Int = DEFAULT_ROWS, columns: Int = DEFAULT_COLUMNS): Board = {
val grid = Array.ofDim[Int](rows, columns)
for (i <- grid.indices) {
for (j <- grid(0).indices) {
grid(i)(j) = Random.nextInt(2)
}
}
Board(grid=grid)
}
def prettyPrint(board: Board): Unit = {
val grid = board.grid
for (i <- grid.indices) {
for (j <- grid(0).indices) {
if (grid(i)(j) == 0) print(" - ") else print(" * ")
}
println()
}
}
}
And my main entry point.
package io.jkratz.katas.gameoflife
object Life {
def main(args: Array[String]): Unit = {
val state0 = Board.random(5,5)
println("State 0")
Board.prettyPrint(state0)
val state1 = state0.evolve()
println("State 1")
Board.prettyPrint(state1)
}
}
functional-programming scala game-of-life
functional-programming scala game-of-life
asked 2 hours ago
jkratz55
101
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
jkratz55
101
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
jkratz55
101
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
jkratz55
101
asked 2 hours ago
jkratz55
101
101
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
jkratz55 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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