Add execution flow editing and connection removal

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

@@ -25,17 +25,17 @@ class ManagerBlockEntity: BlockEntity(ASMR.managerEntityType) {
 			it.position = Point(0.0, 120.0)
 		}
 		val divide = program.addBlock(BinaryOperatorBlock(INT, DIVIDE)) {
-			it.left.link(from = left.output)
-			it.right.link(from = right.output)
+//			it.left.link(from = left.output)
+//			it.right.link(from = right.output)
 			it.position = Point(120.0, 0.0)
 		}
 		val print = program.addBlock(PrintBlock(INT)) {
-			it.input.link(from = divide.output)
+//			it.input.link(from = divide.output)
 			it.position = Point(240.0, 0.0)
 		}
 
-		program.startBlock.executionFlow.link(divide)
-		divide.executionFlow.link(print)
+		program.startBlock.link(divide)
+		divide.link(print)
 	}
 
 	fun activate() {

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

@@ -1,14 +0,0 @@
-package net.shadowfacts.asmr.program
-
-import net.minecraft.util.Identifier
-
-/**
- * @author shadowfacts
- */
-abstract class ExecutableBlock(identifier: Identifier): ProgramBlock(identifier) {
-
-	open val executionFlow = ExecutionFlow(this)
-
-	abstract fun execute()
-
-}

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

@@ -1,16 +0,0 @@
-package net.shadowfacts.asmr.program
-
-/**
- * @author shadowfacts
- */
-open class ExecutionFlow(val block: ExecutableBlock) {
-
-	open var next: ExecutableBlock? = null
-	open var prev: ExecutableBlock? = null
-
-	fun link(next: ExecutableBlock) {
-		this.next = next
-		next.executionFlow.prev = block
-	}
-
-}

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

@@ -1,6 +1,7 @@
 package net.shadowfacts.asmr.program
 
 import net.shadowfacts.asmr.program.blocks.StartBlock
+import net.shadowfacts.asmr.program.execution.ExecutableBlock
 import net.shadowfacts.cacao.geometry.Point
 
 /**
@@ -14,11 +15,11 @@ class Program {
 	val blocks = mutableListOf<ProgramBlock>(startBlock)
 
 	fun execute() {
-		var currentBlock: ExecutableBlock? = startBlock.executionFlow.next
+		var currentBlock: ExecutableBlock? = startBlock.next()
 		while (currentBlock != null) {
 			currentBlock.execute()
 
-			currentBlock = currentBlock.executionFlow.next
+			currentBlock = currentBlock.next()
 		}
 	}
 

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

@@ -27,6 +27,13 @@ class ProgramBlockOutput<Type: Any>(
 		_destinations.remove(to)
 	}
 
+	fun unlinkAll() {
+		for (dest in destinations) {
+			dest.source = null
+		}
+		_destinations.clear()
+	}
+
 	fun translateName(): String {
 		return Language.getInstance().translate("programblock.param.${identifier.namespace}.${identifier.path}")
 	}

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

@@ -3,7 +3,7 @@ package net.shadowfacts.asmr.program
 /**
  * @author shadowfacts
  */
-class ProgramType<Type> {
+class ProgramType<Type: Any> {
 	companion object {
 		val INT = ProgramType<Int>()
 		val FLOAT = ProgramType<Float>()

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

@@ -3,14 +3,14 @@ package net.shadowfacts.asmr.program.blocks
 import net.minecraft.util.Identifier
 import net.shadowfacts.asmr.ASMR
 import net.shadowfacts.asmr.program.*
-import net.shadowfacts.cacao.geometry.Point
+import net.shadowfacts.asmr.program.execution.SimpleExecutableBlock
 
 /**
  * @author shadowfacts
  */
 class PrintBlock<Type: Any>(
 		val type: ProgramType<Type>
-): ExecutableBlock(
+): SimpleExecutableBlock(
 		Identifier(ASMR.modid, "print")
 ) {
 

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

@@ -2,14 +2,13 @@ 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.*
+import net.shadowfacts.asmr.program.execution.SimpleExecutableBlock
 
 /**
  * @author shadowfacts
  */
-class StartBlock: ExecutableBlock(
+class StartBlock: SimpleExecutableBlock(
 		Identifier(ASMR.modid, "start")
 ) {
 

src/main/kotlin/net/shadowfacts/asmr/program/blocks/math/BinaryOperatorBlock.kt

@@ -2,10 +2,8 @@ package net.shadowfacts.asmr.program.blocks.math
 
 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.asmr.program.execution.SimpleExecutableBlock
 import java.lang.RuntimeException
 
 /**
@@ -14,7 +12,7 @@ import java.lang.RuntimeException
 class BinaryOperatorBlock<Type: Any>(
 		val type: ProgramType<Type>,
 		val operation: Operation
-): ExecutableBlock(
+): SimpleExecutableBlock(
 		Identifier(ASMR.modid, "binary_operator")
 ) {
 

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

@@ -0,0 +1,20 @@
+package net.shadowfacts.asmr.program.execution
+
+import net.minecraft.util.Identifier
+import net.shadowfacts.asmr.ASMR
+import net.shadowfacts.asmr.program.ProgramBlock
+
+/**
+ * @author shadowfacts
+ */
+abstract class ExecutableBlock(identifier: Identifier): ProgramBlock(identifier) {
+
+	val incoming = IncomingExecutionFlow(Identifier(ASMR.modid, "incoming"), this)
+	abstract val outgoing: Array<OutgoingExecutionFlow>
+
+	abstract fun execute()
+
+	abstract fun next(): ExecutableBlock?
+
+}
+

src/main/kotlin/net/shadowfacts/asmr/program/execution/IncomingExecutionFlow.kt

@@ -0,0 +1,29 @@
+package net.shadowfacts.asmr.program.execution
+
+import net.minecraft.util.Identifier
+import net.minecraft.util.Language
+
+/**
+ * @author shadowfacts
+ */
+class IncomingExecutionFlow(
+		val identifier: Identifier,
+		val block: ExecutableBlock
+) {
+
+	var source: OutgoingExecutionFlow? = null
+		internal set
+
+	fun link(from: OutgoingExecutionFlow) {
+		from.link(to = this)
+	}
+
+	fun unlink() {
+		source?.unlink()
+	}
+
+	fun translateName(): String {
+		return Language.getInstance().translate("programblock.execution.${identifier.namespace}.${identifier.path}")
+	}
+
+}

src/main/kotlin/net/shadowfacts/asmr/program/execution/OutgoingExecutionFlow.kt

@@ -0,0 +1,31 @@
+package net.shadowfacts.asmr.program.execution
+
+import net.minecraft.util.Identifier
+import net.minecraft.util.Language
+
+/**
+ * @author shadowfacts
+ */
+class OutgoingExecutionFlow(
+		val identifier: Identifier,
+		val block: ExecutableBlock
+) {
+
+	var destination: IncomingExecutionFlow? = null
+		private set
+
+	fun link(to: IncomingExecutionFlow) {
+		destination = to
+		to.source = this
+	}
+
+	fun unlink() {
+		destination?.source = null
+		destination = null
+	}
+
+	fun translateName(): String {
+		return Language.getInstance().translate("programblock.execution.${identifier.namespace}.${identifier.path}")
+	}
+
+}

src/main/kotlin/net/shadowfacts/asmr/program/execution/SimpleExecutableBlock.kt

@@ -0,0 +1,22 @@
+package net.shadowfacts.asmr.program.execution
+
+import net.minecraft.util.Identifier
+import net.shadowfacts.asmr.ASMR
+
+/**
+ * @author shadowfacts
+ */
+abstract class SimpleExecutableBlock(identifier: Identifier): ExecutableBlock(identifier) {
+
+	val outgoingFlow = OutgoingExecutionFlow(Identifier(ASMR.modid, "outgoing"), this)
+	override val outgoing = arrayOf(outgoingFlow)
+
+	override fun next(): ExecutableBlock? {
+		return outgoingFlow.destination?.block
+	}
+
+	fun link(to: ExecutableBlock) {
+		outgoingFlow.link(to.incoming)
+	}
+
+}

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

@@ -1,10 +1,16 @@
 package net.shadowfacts.asmr.ui
 
-import net.shadowfacts.asmr.program.ExecutableBlock
-import net.shadowfacts.asmr.program.Program
-import net.shadowfacts.asmr.program.ProgramBlock
+import net.shadowfacts.asmr.program.*
+import net.shadowfacts.asmr.program.execution.ExecutableBlock
+import net.shadowfacts.asmr.program.execution.IncomingExecutionFlow
+import net.shadowfacts.asmr.program.execution.OutgoingExecutionFlow
+import net.shadowfacts.asmr.ui.block.ProgramBlockConnectionIndicatorView
+import net.shadowfacts.asmr.ui.block.ProgramBlockExecutionView
+import net.shadowfacts.asmr.ui.block.ProgramBlockParamView
+import net.shadowfacts.asmr.ui.block.ProgramBlockView
 import net.shadowfacts.cacao.geometry.Point
 import net.shadowfacts.cacao.util.Color
+import net.shadowfacts.cacao.util.MouseButton
 import net.shadowfacts.cacao.util.RenderHelper
 import net.shadowfacts.cacao.view.View
 
@@ -19,6 +25,8 @@ class ProgramCanvasView(val program: Program): View() {
 	private val executionFlowStartLinks = mutableMapOf<ExecutableBlock, Pair<Point, Point>>()
 	private val parameterLinks = mutableMapOf<ProgramBlock, Pair<Point, Point>>()
 
+	private var currentPartialLink: PartialLink? = null
+
 	override fun wasAdded() {
 		super.wasAdded()
 
@@ -32,15 +40,20 @@ class ProgramCanvasView(val program: Program): View() {
 
 	private fun updateBlockLinks() {
 		for ((startBlock, startView) in blocks) {
-			(startBlock as? ExecutableBlock)?.executionFlow?.next?.let { endBlock ->
-				blocks[endBlock]?.let { endView ->
-					val outgoing = startView.outgoingExeuction!!
-					val incoming = endView.incomingExecution!!
+			(startBlock as? ExecutableBlock)?.let { startBlock ->
+				for (outgoing in startBlock.outgoing) {
+					val outgoingView = startView.outgoingViews[outgoing] ?: continue
+					val start = outgoingView.convert(outgoingView.bounds.center, to = this)
+					val incoming = outgoing.destination
+					if (incoming != null) {
+						val incomingBlockView = blocks[incoming.block] ?: continue
+						val incomingView = incomingBlockView.incomingView!!
+						val end = incomingView.convert(incomingView.bounds.center, to = this)
 
-					val start = outgoing.convert(outgoing.bounds.center, to = this)
-					val end = incoming.convert(outgoing.bounds.center, to = this)
-
-					executionFlowStartLinks[startBlock] = start to end
+						executionFlowStartLinks[startBlock] = start to end
+					} else {
+						executionFlowStartLinks.remove(startBlock)
+					}
 				}
 			}
 
@@ -76,6 +89,202 @@ class ProgramCanvasView(val program: Program): View() {
 		for ((start, end) in parameterLinks.values) {
 			RenderHelper.drawLine(start, end, zIndex, 5f, Color.RED)
 		}
+
+		val currentPartialLink = currentPartialLink
+		if (currentPartialLink != null) {
+			val color = if (currentPartialLink is ParamInputPartialLink<*> || currentPartialLink is ParamOutputPartialLink<*>) Color.RED else Color.GREEN
+			RenderHelper.drawLine(currentPartialLink.startPoint, mouse, zIndex, 5f, color)
+		}
 	}
 
+	override fun mouseClicked(point: Point, mouseButton: MouseButton): Boolean {
+		if (mouseButton == MouseButton.RIGHT && currentPartialLink != null) {
+			this.currentPartialLink = null
+			return true
+		}
+
+		for ((block, blockView) in blocks) {
+			if (convert(point, to = blockView) !in blockView.bounds) continue
+
+			for ((input, inputView) in blockView.inputViews) {
+				if (convert(point, to = inputView) in inputView.bounds) {
+					return inputViewClicked(block, input, inputView, mouseButton)
+				}
+			}
+			for ((output, outputView) in blockView.outputViews) {
+				if (convert(point, to = outputView) in outputView.bounds) {
+					return outputViewClicked(block, output, outputView, mouseButton)
+				}
+			}
+
+			if (block is ExecutableBlock) {
+				if (convert(point, to = blockView.incomingView!!) in blockView.incomingView!!.bounds) {
+					return incomingExecutionViewClicked(block, block.incoming, blockView.incomingView!!, mouseButton)
+				}
+				for ((outgoing, outgoingView) in blockView.outgoingViews) {
+					if (convert(point, to = outgoingView) in outgoingView.bounds) {
+						return outgoingExecutionViewClicked(block, outgoing, outgoingView, mouseButton)
+					}
+				}
+			}
+		}
+
+		return super.mouseClicked(point, mouseButton)
+	}
+
+	private fun <Type: Any> inputViewClicked(block: ProgramBlock, input: ProgramBlockInput<Type>, inputView: ProgramBlockParamView, mouseButton: MouseButton): Boolean {
+		val currentPartialLink = currentPartialLink
+		return if (currentPartialLink == null) {
+			// no partial link in progress
+			when (mouseButton) {
+				MouseButton.LEFT -> {
+					// begin a new one
+					this.currentPartialLink = ParamInputPartialLink(input, inputView, inputView.convert(inputView.bounds.center, to = this))
+					true
+				}
+				MouseButton.RIGHT -> {
+					// clear clicked connection
+					val source = input.source ?: return false
+					val outputView = blocks[source.block]?.outputViews?.get(source) ?: return false
+					input.unlink()
+					inputView.updateTexture()
+					outputView.updateTexture()
+					updateBlockLinks()
+					true
+				}
+				else -> false
+			}
+		} else if (currentPartialLink is ParamOutputPartialLink<*> && currentPartialLink.output.type == input.type)  {
+			// current link in progress originated with an output param of same type as clicked input, so complete it
+			// we can ignore the unchecked cast because we checked it ourselves above by comparing ProgramTypes, but the compiler doesn't know that
+			@Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
+			val currentPartialLink = currentPartialLink as ParamOutputPartialLink<Type>
+			currentPartialLink.output.link(to = input)
+			currentPartialLink.view.updateTexture()
+			inputView.updateTexture()
+			updateBlockLinks()
+			this.currentPartialLink = null
+			true
+		} else {
+			// otherwise, click always fails
+			false
+		}
+	}
+
+	private fun <Type: Any> outputViewClicked(block: ProgramBlock, output: ProgramBlockOutput<Type>, outputView: ProgramBlockParamView, mouseButton: MouseButton): Boolean {
+		val currentPartialLink = currentPartialLink
+		return if (currentPartialLink == null) {
+			// no partial link in progress
+			when (mouseButton) {
+				MouseButton.LEFT -> {
+					// begin a new one
+					this.currentPartialLink = ParamOutputPartialLink(output, outputView, outputView.convert(outputView.bounds.center, to = this))
+					true
+				}
+				MouseButton.RIGHT -> {
+					// clear clicked connection
+					val inputViews = output.destinations.mapNotNull { blocks[it.block]?.inputViews?.get(it) }
+					output.unlinkAll()
+					outputView.updateTexture()
+					inputViews.forEach(ProgramBlockParamView::updateTexture)
+					updateBlockLinks()
+					true
+				}
+				else -> false
+			}
+		} else if (currentPartialLink is ParamInputPartialLink<*> && currentPartialLink.input.type == output.type) {
+			// current link in progress originated with an input param of same type as clicked output, so complete it
+			// we can ignore the unchecked cast because we checked it ourselves above by comparing ProgramTypes, but the compiler doesn't know that
+			@Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
+			val currentPartialLink = currentPartialLink as ParamInputPartialLink<Type>
+			currentPartialLink.input.link(from = output)
+			currentPartialLink.view.updateTexture()
+			outputView.updateTexture()
+			updateBlockLinks()
+			this.currentPartialLink = null
+			true
+		} else {
+			// otherwise, click always fails
+			false
+		}
+	}
+
+	private fun incomingExecutionViewClicked(block: ProgramBlock, incoming: IncomingExecutionFlow, incomingView: ProgramBlockExecutionView, mouseButton: MouseButton): Boolean {
+		val currentPartialLink = currentPartialLink
+		return if (currentPartialLink == null) {
+			// no partial link in progress
+			when (mouseButton) {
+				MouseButton.LEFT -> {
+					// being a new one
+					this.currentPartialLink = IncomingExecutionPartialLink(incoming, incomingView, incomingView.convert(incomingView.bounds.center, to = this))
+					true
+				}
+				MouseButton.RIGHT -> {
+					// clear clicked connection
+					val outgoing = incoming.source ?: return false
+					val outgoingView = blocks[outgoing.block]?.outgoingViews?.get(outgoing) ?: return false
+					incoming.unlink()
+					incomingView.updateTexture()
+					outgoingView.updateTexture()
+					updateBlockLinks()
+					true
+				}
+				else -> false
+			}
+		} else if (currentPartialLink is OutgoingExecutionPartialLink) {
+			// current link in progress originated with an outgoing execution connection, so complete it
+			currentPartialLink.outgoing.link(incoming)
+			currentPartialLink.view.updateTexture()
+			incomingView.updateTexture()
+			updateBlockLinks()
+			this.currentPartialLink = null
+			true
+		} else {
+			// otherwise, click always fails
+			false
+		}
+	}
+
+	private fun outgoingExecutionViewClicked(block: ProgramBlock, outgoing: OutgoingExecutionFlow, outgoingView: ProgramBlockExecutionView, mouseButton: MouseButton): Boolean {
+		val currentPartialLink = currentPartialLink
+		return if (currentPartialLink == null) {
+			// no partial link in progress
+			when (mouseButton) {
+				MouseButton.LEFT -> {
+					// begin a new one
+					this.currentPartialLink = OutgoingExecutionPartialLink(outgoing, outgoingView, outgoingView.convert(outgoingView.bounds.center, to = this))
+					true
+				}
+				MouseButton.RIGHT -> {
+					// clear clicked connection
+					val incoming = outgoing.destination ?: return false
+					val incomingView = blocks[incoming.block]?.incomingView ?: return false
+					outgoing.unlink()
+					outgoingView.updateTexture()
+					incomingView.updateTexture()
+					updateBlockLinks()
+					true
+				}
+				else -> false
+			}
+		} else if (currentPartialLink is IncomingExecutionPartialLink) {
+			// current link in progress originated with an incoming execution connection, so complete it
+			currentPartialLink.incoming.link(outgoing)
+			currentPartialLink.view.updateTexture()
+			outgoingView.updateTexture()
+			updateBlockLinks()
+			this.currentPartialLink = null
+			true
+		} else {
+			// otherwise, click always fails
+			false
+		}
+	}
+
+	open class PartialLink(val view: ProgramBlockConnectionIndicatorView, val startPoint: Point)
+	class ParamInputPartialLink<Type: Any>(val input: ProgramBlockInput<Type>, view: ProgramBlockParamView, startPoint: Point): PartialLink(view, startPoint)
+	class ParamOutputPartialLink<Type: Any>(val output: ProgramBlockOutput<Type>, view: ProgramBlockParamView, startPoint: Point): PartialLink(view, startPoint)
+	class IncomingExecutionPartialLink(val incoming: IncomingExecutionFlow, view: ProgramBlockExecutionView, startPoint: Point): PartialLink(view, startPoint)
+	class OutgoingExecutionPartialLink(val outgoing: OutgoingExecutionFlow, view: ProgramBlockExecutionView, startPoint: Point): PartialLink(view, startPoint)
+
 }

src/main/kotlin/net/shadowfacts/asmr/ui/block/ProgramBlockConnectionIndicatorView.kt

@@ -0,0 +1,12 @@
+package net.shadowfacts.asmr.ui.block
+
+import net.shadowfacts.cacao.view.View
+
+/**
+ * @author shadowfacts
+ */
+interface ProgramBlockConnectionIndicatorView {
+
+	fun updateTexture()
+
+}

src/main/kotlin/net/shadowfacts/asmr/ui/block/ProgramBlockExecutionView.kt

@@ -0,0 +1,53 @@
+package net.shadowfacts.asmr.ui.block
+
+import net.minecraft.util.Identifier
+import net.shadowfacts.asmr.ASMR
+import net.shadowfacts.asmr.program.execution.IncomingExecutionFlow
+import net.shadowfacts.asmr.program.execution.OutgoingExecutionFlow
+import net.shadowfacts.cacao.util.texture.Texture
+import net.shadowfacts.cacao.view.TextureView
+import net.shadowfacts.cacao.view.View
+import net.shadowfacts.kiwidsl.dsl
+import java.lang.RuntimeException
+
+/**
+ * @author shadowfacts
+ */
+class ProgramBlockExecutionView(val incoming: IncomingExecutionFlow?, val outgoing: OutgoingExecutionFlow?): View(), ProgramBlockConnectionIndicatorView {
+
+	companion object {
+		val emptyConnection = Texture(Identifier(ASMR.modid, "textures/gui/programmer/program_connections.png"), u = 0, v = 0)
+		val executionConnection = Texture(Identifier(ASMR.modid, "textures/gui/programmer/program_connections.png"), u = 7, v = 0)
+	}
+
+	lateinit var textureView: TextureView
+
+	constructor(incoming: IncomingExecutionFlow?): this(incoming, null)
+	constructor(outgoing: OutgoingExecutionFlow?): this(null, outgoing)
+
+	init {
+		if (incoming == null && outgoing == null) {
+			throw RuntimeException("One of incoming or outgoing must be non-null")
+		}
+	}
+
+	override fun wasAdded() {
+		super.wasAdded()
+
+		textureView = addSubview(TextureView(emptyConnection))
+		updateTexture()
+
+		solver.dsl {
+			textureView.leftAnchor equalTo leftAnchor
+			textureView.rightAnchor equalTo rightAnchor
+			textureView.topAnchor equalTo topAnchor
+			textureView.bottomAnchor equalTo bottomAnchor
+		}
+	}
+
+	override fun updateTexture() {
+		val active = if (incoming != null) incoming.source != null else outgoing!!.destination != null
+		textureView.texture = if (active) executionConnection else emptyConnection
+	}
+
+}

src/main/kotlin/net/shadowfacts/asmr/ui/block/ProgramBlockParamView.kt

@@ -0,0 +1,53 @@
+package net.shadowfacts.asmr.ui.block
+
+import net.minecraft.util.Identifier
+import net.shadowfacts.asmr.ASMR
+import net.shadowfacts.asmr.program.ProgramBlockInput
+import net.shadowfacts.asmr.program.ProgramBlockOutput
+import net.shadowfacts.cacao.util.texture.Texture
+import net.shadowfacts.cacao.view.TextureView
+import net.shadowfacts.cacao.view.View
+import net.shadowfacts.kiwidsl.dsl
+import java.lang.RuntimeException
+
+/**
+ * @author shadowfacts
+ */
+class ProgramBlockParamView(val input: ProgramBlockInput<*>?, val output: ProgramBlockOutput<*>?): View(), ProgramBlockConnectionIndicatorView {
+
+	companion object {
+		val emptyConnection = Texture(Identifier(ASMR.modid, "textures/gui/programmer/program_connections.png"), u = 0, v = 0)
+		val parameterConnection = Texture(Identifier(ASMR.modid, "textures/gui/programmer/program_connections.png"), u = 14, v = 0)
+	}
+
+	lateinit var textureView: TextureView
+
+	constructor(input: ProgramBlockInput<*>): this(input, null)
+	constructor(output: ProgramBlockOutput<*>): this(null, output)
+
+	init {
+		if (input == null && output == null) {
+			throw RuntimeException("One of input or output must be non-null")
+		}
+	}
+
+	override fun wasAdded() {
+		super.wasAdded()
+
+		textureView = addSubview(TextureView(emptyConnection))
+		updateTexture()
+
+		solver.dsl {
+			textureView.leftAnchor equalTo leftAnchor
+			textureView.rightAnchor equalTo rightAnchor
+			textureView.topAnchor equalTo topAnchor
+			textureView.bottomAnchor equalTo bottomAnchor
+		}
+	}
+
+	override fun updateTexture() {
+		val active = if (input != null) input.source != null else output!!.destinations.isNotEmpty()
+		textureView.texture = if (active) parameterConnection else emptyConnection
+	}
+
+}

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

@@ -1,11 +1,12 @@
-package net.shadowfacts.asmr.ui
+package net.shadowfacts.asmr.ui.block
 
 import net.minecraft.util.Identifier
 import net.shadowfacts.asmr.ASMR
-import net.shadowfacts.asmr.program.ExecutableBlock
+import net.shadowfacts.asmr.program.execution.ExecutableBlock
 import net.shadowfacts.asmr.program.ProgramBlock
 import net.shadowfacts.asmr.program.ProgramBlockInput
 import net.shadowfacts.asmr.program.ProgramBlockOutput
+import net.shadowfacts.asmr.program.execution.OutgoingExecutionFlow
 import net.shadowfacts.cacao.geometry.Axis
 import net.shadowfacts.cacao.geometry.Point
 import net.shadowfacts.cacao.util.Color
@@ -13,7 +14,6 @@ import net.shadowfacts.cacao.util.MouseButton
 import net.shadowfacts.cacao.util.texture.Texture
 import net.shadowfacts.cacao.view.Label
 import net.shadowfacts.cacao.view.StackView
-import net.shadowfacts.cacao.view.TextureView
 import net.shadowfacts.cacao.view.View
 import net.shadowfacts.kiwidsl.dsl
 import no.birkett.kiwi.Constraint
@@ -30,11 +30,11 @@ class ProgramBlockView(val block: ProgramBlock): StackView(Axis.VERTICAL, Distri
 		val parameterConnection = Texture(Identifier(ASMR.modid, "textures/gui/programmer/program_connections.png"), u = 14, v = 0)
 	}
 
-	var incomingExecution: View? = null
-	var outgoingExeuction: View? = null
+	var incomingView: ProgramBlockExecutionView? = null
+	val outgoingViews = mutableMapOf<OutgoingExecutionFlow, ProgramBlockExecutionView>()
 
-	val inputViews = mutableMapOf<ProgramBlockInput<*>, View>()
-	val outputViews = mutableMapOf<ProgramBlockOutput<*>, View>()
+	val inputViews = mutableMapOf<ProgramBlockInput<*>, ProgramBlockParamView>()
+	val outputViews = mutableMapOf<ProgramBlockOutput<*>, ProgramBlockParamView>()
 
 	var xConstraint: Constraint? = null
 	var yConstraint: Constraint? = null
@@ -49,23 +49,33 @@ class ProgramBlockView(val block: ProgramBlock): StackView(Axis.VERTICAL, Distri
 		zIndex = 10.0
 
 		val titleStack = addArrangedSubview(StackView(Axis.HORIZONTAL, Distribution.CENTER))
-		val title = titleStack.addArrangedSubview(Label(block.translateName(), wrappingMode = Label.WrappingMode.NO_WRAP))
 		if (block is ExecutableBlock) {
-			val incomingTexture = if (block.executionFlow.prev == null) emptyConnection else executionConnection
-			incomingExecution = titleStack.addArrangedSubview(TextureView(incomingTexture), index = 0)
-			val outgoingTexture = if (block.executionFlow.next == null) emptyConnection else executionConnection
-			outgoingExeuction = titleStack.addArrangedSubview(TextureView(outgoingTexture))
+			incomingView = titleStack.addArrangedSubview(ProgramBlockExecutionView(block.incoming))
 		}
+		val title = titleStack.addArrangedSubview(Label(block.translateName(), wrappingMode = Label.WrappingMode.NO_WRAP))
 
 		solver.dsl {
 			// we have to constrain the titleStack height, because it's distribution is set to CENTER, so it doesn't do it itself
 			titleStack.heightAnchor equalTo title.heightAnchor
 
 			if (block is ExecutableBlock) {
-				incomingExecution!!.widthAnchor equalTo incomingExecution!!.heightAnchor
-				incomingExecution!!.widthAnchor equalTo 7
-				outgoingExeuction!!.widthAnchor equalTo outgoingExeuction!!.heightAnchor
-				outgoingExeuction!!.widthAnchor equalTo 7
+				incomingView!!.widthAnchor equalTo incomingView!!.heightAnchor
+				incomingView!!.widthAnchor equalTo 7
+			}
+		}
+
+		if (block is ExecutableBlock) {
+			for (outgoing in block.outgoing) {
+				val hStack = addArrangedSubview(StackView(Axis.HORIZONTAL, Distribution.CENTER))
+				val outgoingLabel = hStack.addArrangedSubview(Label(outgoing.translateName(), wrappingMode = Label.WrappingMode.NO_WRAP, textAlignment = Label.TextAlignment.RIGHT))
+				val outgoingView = hStack.addArrangedSubview(ProgramBlockExecutionView(outgoing))
+				outgoingViews[outgoing] = outgoingView
+				solver.dsl {
+					hStack.heightAnchor equalTo outgoingLabel.heightAnchor
+
+					outgoingView.widthAnchor equalTo outgoingView.heightAnchor
+					outgoingView.widthAnchor equalTo 7
+				}
 			}
 		}
 
@@ -73,10 +83,9 @@ class ProgramBlockView(val block: ProgramBlock): StackView(Axis.VERTICAL, Distri
 			val hStack = addArrangedSubview(StackView(Axis.HORIZONTAL, Distribution.CENTER))
 
 			block.inputs.getOrNull(i)?.let { input ->
-				val inputTexture = if (input.source == null) emptyConnection else parameterConnection
-				val inputView = hStack.addArrangedSubview(TextureView(inputTexture))
+				val inputView = hStack.addArrangedSubview(ProgramBlockParamView(input))
 				inputViews[input] = inputView
-				val inputLabel = hStack.addArrangedSubview(Label(input.translateName()))
+				val inputLabel = hStack.addArrangedSubview(Label(input.translateName(), wrappingMode = Label.WrappingMode.NO_WRAP))
 				solver.dsl {
 					hStack.heightAnchor equalTo inputLabel.heightAnchor
 
@@ -91,9 +100,8 @@ class ProgramBlockView(val block: ProgramBlock): StackView(Axis.VERTICAL, Distri
 			}
 
 			block.outputs.getOrNull(i)?.let { output ->
-				val outputLabel = hStack.addArrangedSubview(Label(output.translateName(), textAlignment = Label.TextAlignment.RIGHT))
-				val outputTexture = if (output.destinations.isEmpty()) emptyConnection else parameterConnection
-				val outputView = hStack.addArrangedSubview(TextureView(outputTexture))
+				val outputLabel = hStack.addArrangedSubview(Label(output.translateName(), wrappingMode = Label.WrappingMode.NO_WRAP, textAlignment = Label.TextAlignment.RIGHT))
+				val outputView = hStack.addArrangedSubview(ProgramBlockParamView(output))
 				outputViews[output] = outputView
 				solver.dsl {
 					hStack.heightAnchor equalTo outputLabel.heightAnchor
@@ -124,7 +132,7 @@ class ProgramBlockView(val block: ProgramBlock): StackView(Axis.VERTICAL, Distri
 
 			arrangedSubviews.maxBy { it.bounds.width }?.let { widestSubview ->
 				solver.dsl {
-					widthAnchor equalTo widestSubview.widthAnchor
+					widthAnchor equalTo widestSubview.bounds.width
 				}
 				window!!.layout()
 			}

src/main/resources/assets/asmr/lang/en_us.json

@@ -1,4 +1,6 @@
 {
+	"programblock.execution.asmr.incoming": "Incoming",
+	"programblock.execution.asmr.outgoing": "Outgoing",
 	"programblock.asmr.start": "Start",
 	"programblock.asmr.constant": "Constant",
 	"programblock.param.asmr.constant.output": "Output",

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

@@ -20,7 +20,7 @@ class ProgramTests {
 			it.right.link(from = two.output)
 		}
 
-		program.startBlock.executionFlow.link(multiply)
+		program.startBlock.link(multiply)
 
 		program.execute()