Refactor program execution flow to link bidirectionally

src/main/kotlin/net/shadowfacts/asmr/manager/ManagerBlockEntity.kt

@@ -34,8 +34,8 @@ class ManagerBlockEntity: BlockEntity(ASMR.managerEntityType) {
 			it.position = Point(240.0, 0.0)
 		}
 
-		program.startBlock.nextExecutableBlock = divide
-		divide.nextExecutableBlock = print
+		program.startBlock.linkNext(divide)
+		divide.linkNext(print)
 	}
 
 	fun activate() {

src/main/kotlin/net/shadowfacts/asmr/program/ExecutableBlock.kt

@@ -1,14 +1,17 @@
 package net.shadowfacts.asmr.program
 
-import net.shadowfacts.cacao.geometry.Point
-
 /**
  * @author shadowfacts
  */
 abstract class ExecutableBlock: ProgramBlock() {
 
-	var nextExecutableBlock: ExecutableBlock? = null
+	open val executionFlow = ExecutionFlow()
 
 	abstract fun execute()
 
+	fun linkNext(next: ExecutableBlock) {
+		executionFlow.next = next
+		next.executionFlow.prev = this
+	}
+
 }

src/main/kotlin/net/shadowfacts/asmr/program/ExecutionFlow.kt

@@ -0,0 +1,11 @@
+package net.shadowfacts.asmr.program
+
+/**
+ * @author shadowfacts
+ */
+open class ExecutionFlow {
+
+	open var next: ExecutableBlock? = null
+	open var prev: ExecutableBlock? = null
+
+}

src/main/kotlin/net/shadowfacts/asmr/program/Program.kt

@@ -14,11 +14,11 @@ class Program {
 	val blocks = mutableListOf<ProgramBlock>()
 
 	fun execute() {
-		var currentBlock: ExecutableBlock? = startBlock.nextExecutableBlock
+		var currentBlock: ExecutableBlock? = startBlock.executionFlow.next
 		while (currentBlock != null) {
 			currentBlock.execute()
 
-			currentBlock = currentBlock.nextExecutableBlock
+			currentBlock = currentBlock.executionFlow.next
 		}
 	}
 

src/main/kotlin/net/shadowfacts/asmr/program/blocks/PrintBlock.kt

@@ -2,10 +2,7 @@ package net.shadowfacts.asmr.program.blocks
 
 import net.minecraft.util.Identifier
 import net.shadowfacts.asmr.ASMR
-import net.shadowfacts.asmr.program.ExecutableBlock
-import net.shadowfacts.asmr.program.ProgramBlockInput
-import net.shadowfacts.asmr.program.ProgramBlockOutput
-import net.shadowfacts.asmr.program.ProgramType
+import net.shadowfacts.asmr.program.*
 import net.shadowfacts.cacao.geometry.Point
 
 /**

src/main/kotlin/net/shadowfacts/asmr/program/blocks/StartBlock.kt

@@ -1,18 +1,18 @@
 package net.shadowfacts.asmr.program.blocks
 
 import net.shadowfacts.asmr.program.ExecutableBlock
-import net.shadowfacts.asmr.program.ProgramBlock
 import net.shadowfacts.asmr.program.ProgramBlockInput
 import net.shadowfacts.asmr.program.ProgramBlockOutput
 
 /**
  * @author shadowfacts
  */
-class StartBlock: ProgramBlock() {
+class StartBlock: ExecutableBlock() {
 
 	override val inputs: Array<ProgramBlockInput<*>> = arrayOf()
 	override val outputs: Array<ProgramBlockOutput<*>> = arrayOf()
 
-	var nextExecutableBlock: ExecutableBlock? = null
+	override fun execute() {
+	}
 
 }

src/main/kotlin/net/shadowfacts/asmr/ui/ProgramBlockView.kt

@@ -43,9 +43,9 @@ class ProgramBlockView(val block: ProgramBlock): StackView(Axis.VERTICAL, Distri
 		val titleStack = addArrangedSubview(StackView(Axis.HORIZONTAL, Distribution.CENTER))
 		val title = titleStack.addArrangedSubview(Label(block.javaClass.simpleName))
 		if (block is ExecutableBlock) {
-			val incomingTexture = executionFlowInactiveTexture
+			val incomingTexture = if (block.executionFlow.prev == null) executionFlowInactiveTexture else executionFlowActiveTexture
 			incomingExecution = titleStack.addArrangedSubview(TextureView(incomingTexture), index = 0)
-			val outgoingTexture = if (block.nextExecutableBlock == null) executionFlowInactiveTexture else executionFlowActiveTexture
+			val outgoingTexture = if (block.executionFlow.next == null) executionFlowInactiveTexture else executionFlowActiveTexture
 			outgoingExeuction = titleStack.addArrangedSubview(TextureView(outgoingTexture))
 		}
 

src/main/kotlin/net/shadowfacts/asmr/ui/ProgramCanvasView.kt

@@ -31,7 +31,7 @@ class ProgramCanvasView(val program: Program): View() {
 
 
 		for ((block, view) in blocks) {
-			(block as? ExecutableBlock)?.nextExecutableBlock?.let { next ->
+			(block as? ExecutableBlock)?.executionFlow?.next?.let { next ->
 				blocks[next]?.let { nextView ->
 					val outgoing = view.outgoingExeuction!!
 					val incoming = nextView.incomingExecution!!

src/test/kotlin/net/shadowfacts/asmr/program/ProgramTests.kt

@@ -20,7 +20,7 @@ class ProgramTests {
 			it.right.source = two.output
 		}
 
-		program.startBlock.nextExecutableBlock = multiply
+		program.startBlock.linkNext(multiply)
 
 		program.execute()