Properties refactoring

dataforge-device-core/src/commonMain/kotlin/hep/dataforge/control/base/DeviceBase.kt

@@ -45,6 +45,10 @@ abstract class DeviceBase : Device {
         return properties.getOrPut(name, builder)
     }
 
+    internal fun registerMutableProperty(name: String, builder: () -> DeviceProperty): DeviceProperty {
+        return properties.getOrPut(name, builder) as DeviceProperty
+    }
+
     internal fun registerAction(name: String, builder: () -> Action): Action {
         return actions.getOrPut(name, builder)
     }

dataforge-device-core/src/commonMain/kotlin/hep/dataforge/control/base/DeviceProperty.kt

@@ -9,52 +9,52 @@ import kotlin.time.Duration
 /**
  * Read-only device property
  */
-interface ReadOnlyDeviceProperty {
+public interface ReadOnlyDeviceProperty {
     /**
      * Property name, should be unique in device
      */
-    val name: String
+    public val name: String
 
     /**
      * Property descriptor
      */
-    val descriptor: PropertyDescriptor
+    public val descriptor: PropertyDescriptor
 
-    val scope: CoroutineScope
+    public val scope: CoroutineScope
 
     /**
      * Erase logical value and force re-read from device on next [read]
      */
-    suspend fun invalidate()
+    public suspend fun invalidate()
+
+    /**
+     * Directly update property logical value and notify listener without writing it to device
+     */
+    public fun updateLogical(item: MetaItem<*>)
 
-//    /**
-//     * Update property logical value and notify listener without writing it to device
-//     */
-//    suspend fun update(item: MetaItem<*>)
-//
     /**
      *  Get cached value and return null if value is invalid or not initialized
      */
-    val value: MetaItem<*>?
+    public val value: MetaItem<*>?
 
     /**
      * Read value either from cache if cache is valid or directly from physical device.
-     * If [force], reread
+     * If [force], reread from physical state even if the logical state is set.
      */
-    suspend fun read(force: Boolean = false): MetaItem<*>
+    public suspend fun read(force: Boolean = false): MetaItem<*>
 
     /**
      * The [Flow] representing future logical states of the property.
      * Produces null when the state is invalidated
      */
-    fun flow(): Flow<MetaItem<*>?>
+    public fun flow(): Flow<MetaItem<*>?>
 }
 
 
 /**
  * Launch recurring force re-read job on a property scope with given [duration] between reads.
  */
-fun ReadOnlyDeviceProperty.readEvery(duration: Duration): Job = scope.launch {
+public fun ReadOnlyDeviceProperty.readEvery(duration: Duration): Job = scope.launch {
     while (isActive) {
         read(true)
         delay(duration)
@@ -64,11 +64,11 @@ fun ReadOnlyDeviceProperty.readEvery(duration: Duration): Job = scope.launch {
 /**
  * A writeable device property with non-suspended write
  */
-interface DeviceProperty : ReadOnlyDeviceProperty {
+public interface DeviceProperty : ReadOnlyDeviceProperty {
     override var value: MetaItem<*>?
 
     /**
      * Write value to physical device. Invalidates logical value, but does not update it automatically
      */
-    suspend fun write(item: MetaItem<*>)
+    public suspend fun write(item: MetaItem<*>)
 }

dataforge-device-core/src/commonMain/kotlin/hep/dataforge/control/base/IsolatedDeviceProperty.kt

@@ -1,10 +1,8 @@
 package hep.dataforge.control.base
 
 import hep.dataforge.control.api.PropertyDescriptor
-import hep.dataforge.meta.Meta
+import hep.dataforge.meta.*
-import hep.dataforge.meta.MetaBuilder
+import hep.dataforge.values.Null
-import hep.dataforge.meta.MetaItem
-import hep.dataforge.meta.double
 import hep.dataforge.values.Value
 import hep.dataforge.values.asValue
 import kotlinx.coroutines.CoroutineScope
@@ -26,7 +24,7 @@ private fun DeviceBase.propertyChanged(name: String, item: MetaItem<*>?){
  * A stand-alone [ReadOnlyDeviceProperty] implementation not directly attached to a device
  */
 @OptIn(ExperimentalCoroutinesApi::class)
-open class IsolatedReadOnlyDeviceProperty(
+public open class IsolatedReadOnlyDeviceProperty(
     override val name: String,
     default: MetaItem<*>?,
     override val descriptor: PropertyDescriptor,
@@ -42,7 +40,7 @@ open class IsolatedReadOnlyDeviceProperty(
         state.value = null
     }
 
-    protected fun update(item: MetaItem<*>) {
+    override fun updateLogical(item: MetaItem<*>) {
         state.value = item
         callback(name, item)
     }
@@ -56,7 +54,7 @@ open class IsolatedReadOnlyDeviceProperty(
                 //TODO add error catching
                 getter(currentValue)
             }
-            update(res)
+            updateLogical(res)
             res
         } else {
             currentValue
@@ -66,7 +64,7 @@ open class IsolatedReadOnlyDeviceProperty(
     override fun flow(): StateFlow<MetaItem<*>?> = state
 }
 
-fun DeviceBase.readOnlyProperty(
+public fun DeviceBase.readOnlyProperty(
     name: String,
     default: MetaItem<*>?,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
@@ -87,9 +85,9 @@ private class ReadOnlyDevicePropertyDelegate<D : DeviceBase>(
     val default: MetaItem<*>?,
     val descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     private val getter: suspend (MetaItem<*>?) -> MetaItem<*>
-) : ReadOnlyProperty<D, IsolatedReadOnlyDeviceProperty> {
+) : ReadOnlyProperty<D, ReadOnlyDeviceProperty> {
 
-    override fun getValue(thisRef: D, property: KProperty<*>): IsolatedReadOnlyDeviceProperty {
+    override fun getValue(thisRef: D, property: KProperty<*>): ReadOnlyDeviceProperty {
         val name = property.name
 
         return owner.registerProperty(name) {
@@ -102,37 +100,37 @@ private class ReadOnlyDevicePropertyDelegate<D : DeviceBase>(
                 owner::propertyChanged,
                 getter
             )
-        } as IsolatedReadOnlyDeviceProperty
+        }
     }
 }
 
-fun <D : DeviceBase> D.reading(
+public fun <D : DeviceBase> D.reading(
     default: MetaItem<*>? = null,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     getter: suspend (MetaItem<*>?) -> MetaItem<*>
-): ReadOnlyProperty<D, IsolatedReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
+): ReadOnlyProperty<D, ReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
     this,
     default,
     descriptorBuilder,
     getter
 )
 
-fun <D : DeviceBase> D.readingValue(
+public fun <D : DeviceBase> D.readingValue(
     default: Value? = null,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
-    getter: suspend () -> Any
+    getter: suspend () -> Any?
-): ReadOnlyProperty<D, IsolatedReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
+): ReadOnlyProperty<D, ReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
     this,
     default?.let { MetaItem.ValueItem(it) },
     descriptorBuilder,
     getter = { MetaItem.ValueItem(Value.of(getter())) }
 )
 
-fun <D : DeviceBase> D.readingNumber(
+public fun <D : DeviceBase> D.readingNumber(
     default: Number? = null,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     getter: suspend () -> Number
-): ReadOnlyProperty<D, IsolatedReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
+): ReadOnlyProperty<D, ReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
     this,
     default?.let { MetaItem.ValueItem(it.asValue()) },
     descriptorBuilder,
@@ -142,11 +140,25 @@ fun <D : DeviceBase> D.readingNumber(
     }
 )
 
-fun <D : DeviceBase> D.readingMeta(
+public fun <D : DeviceBase> D.readingString(
+    default: Number? = null,
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    getter: suspend () -> String
+): ReadOnlyProperty<D, ReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
+    this,
+    default?.let { MetaItem.ValueItem(it.asValue()) },
+    descriptorBuilder,
+    getter = {
+        val number = getter()
+        MetaItem.ValueItem(number.asValue())
+    }
+)
+
+public fun <D : DeviceBase> D.readingMeta(
     default: Meta? = null,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     getter: suspend MetaBuilder.() -> Unit
-): ReadOnlyProperty<D, IsolatedReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
+): ReadOnlyProperty<D, ReadOnlyDeviceProperty> = ReadOnlyDevicePropertyDelegate(
     this,
     default?.let { MetaItem.NodeItem(it) },
     descriptorBuilder,
@@ -156,7 +168,7 @@ fun <D : DeviceBase> D.readingMeta(
 )
 
 @OptIn(ExperimentalCoroutinesApi::class)
-class IsolatedDeviceProperty(
+public class IsolatedDeviceProperty(
     name: String,
     default: MetaItem<*>?,
     descriptor: PropertyDescriptor,
@@ -189,20 +201,20 @@ class IsolatedDeviceProperty(
             withContext(scope.coroutineContext) {
                 //TODO add error catching
                 setter(oldValue, item)?.let {
-                    update(it)
+                    updateLogical(it)
                 }
             }
         }
     }
 }
 
-fun DeviceBase.mutableProperty(
+public fun DeviceBase.mutableProperty(
     name: String,
     default: MetaItem<*>?,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     getter: suspend (MetaItem<*>?) -> MetaItem<*>,
     setter: suspend (oldValue: MetaItem<*>?, newValue: MetaItem<*>) -> MetaItem<*>?
-): ReadOnlyDeviceProperty = registerProperty(name) {
+): DeviceProperty = registerMutableProperty(name) {
     IsolatedDeviceProperty(
         name,
         default,
@@ -220,11 +232,11 @@ private class DevicePropertyDelegate<D : DeviceBase>(
     val descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     private val getter: suspend (MetaItem<*>?) -> MetaItem<*>,
     private val setter: suspend (oldValue: MetaItem<*>?, newValue: MetaItem<*>) -> MetaItem<*>?
-) : ReadOnlyProperty<D, IsolatedDeviceProperty> {
+) : ReadOnlyProperty<D, DeviceProperty> {
 
     override fun getValue(thisRef: D, property: KProperty<*>): IsolatedDeviceProperty {
         val name = property.name
-        return owner.registerProperty(name) {
+        return owner.registerMutableProperty(name) {
             @OptIn(ExperimentalCoroutinesApi::class)
             IsolatedDeviceProperty(
                 name,
@@ -239,12 +251,12 @@ private class DevicePropertyDelegate<D : DeviceBase>(
     }
 }
 
-fun <D : DeviceBase> D.writing(
+public fun <D : DeviceBase> D.writing(
     default: MetaItem<*>? = null,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     getter: suspend (MetaItem<*>?) -> MetaItem<*>,
     setter: suspend (oldValue: MetaItem<*>?, newValue: MetaItem<*>) -> MetaItem<*>?
-): ReadOnlyProperty<D, IsolatedDeviceProperty> = DevicePropertyDelegate(
+): ReadOnlyProperty<D, DeviceProperty> = DevicePropertyDelegate(
     this,
     default,
     descriptorBuilder,
@@ -252,31 +264,31 @@ fun <D : DeviceBase> D.writing(
     setter
 )
 
-fun <D : DeviceBase> D.writingVirtual(
+public fun <D : DeviceBase> D.writingVirtual(
     default: MetaItem<*>,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {}
-): ReadOnlyProperty<D, IsolatedDeviceProperty> = writing(
+): ReadOnlyProperty<D, DeviceProperty> = writing(
     default,
     descriptorBuilder,
     getter = { it ?: default },
     setter = { _, newItem -> newItem }
 )
 
-fun <D : DeviceBase> D.writingVirtual(
+public fun <D : DeviceBase> D.writingVirtual(
     default: Value,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {}
-): ReadOnlyProperty<D, IsolatedDeviceProperty> = writing(
+): ReadOnlyProperty<D, DeviceProperty> = writing(
     MetaItem.ValueItem(default),
     descriptorBuilder,
     getter = { it ?: MetaItem.ValueItem(default) },
     setter = { _, newItem -> newItem }
 )
 
-fun <D : DeviceBase> D.writingDouble(
+public fun <D : DeviceBase> D.writingDouble(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     getter: suspend (Double) -> Double,
     setter: suspend (oldValue: Double?, newValue: Double) -> Double?
-): ReadOnlyProperty<D, IsolatedDeviceProperty> {
+): ReadOnlyProperty<D, DeviceProperty> {
     val innerGetter: suspend (MetaItem<*>?) -> MetaItem<*> = {
         MetaItem.ValueItem(getter(it.double ?: Double.NaN).asValue())
     }
@@ -293,3 +305,25 @@ fun <D : DeviceBase> D.writingDouble(
         innerSetter
     )
 }
+
+public fun <D : DeviceBase> D.writingBoolean(
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    getter: suspend (Boolean?) -> Boolean,
+    setter: suspend (oldValue: Boolean?, newValue: Boolean) -> Boolean?
+): ReadOnlyProperty<D, DeviceProperty> {
+    val innerGetter: suspend (MetaItem<*>?) -> MetaItem<*> = {
+        MetaItem.ValueItem(getter(it.boolean).asValue())
+    }
+
+    val innerSetter: suspend (oldValue: MetaItem<*>?, newValue: MetaItem<*>) -> MetaItem<*>? = { oldValue, newValue ->
+        setter(oldValue.boolean, newValue.boolean?: error("Can't convert $newValue to boolean"))?.asValue()?.asMetaItem()
+    }
+
+    return DevicePropertyDelegate(
+        this,
+        MetaItem.ValueItem(Null),
+        descriptorBuilder,
+        innerGetter,
+        innerSetter
+    )
+}

dataforge-device-core/src/commonMain/kotlin/hep/dataforge/control/controllers/DeviceController.kt

@@ -5,6 +5,7 @@ import hep.dataforge.control.api.DeviceHub
 import hep.dataforge.control.api.DeviceListener
 import hep.dataforge.control.api.get
 import hep.dataforge.control.controllers.DeviceMessage.Companion.PROPERTY_CHANGED_ACTION
+import hep.dataforge.io.Consumer
 import hep.dataforge.io.Envelope
 import hep.dataforge.io.Responder
 import hep.dataforge.io.SimpleEnvelope
@@ -168,7 +169,7 @@ class DeviceController(
 suspend fun DeviceHub.respondMessage(request: DeviceMessage): DeviceMessage {
     return try {
         val targetName = request.target?.toName() ?: Name.EMPTY
-        val device = this[targetName]
+        val device = this[targetName] ?: error("The device with name $targetName not found in $this")
         DeviceController.respondMessage(device, targetName.toString(), request)
     } catch (ex: Exception) {
         DeviceMessage.fail {

dataforge-device-core/src/commonMain/kotlin/hep/dataforge/control/controllers/DeviceManager.kt

@@ -8,6 +8,7 @@ import hep.dataforge.control.api.Device
 import hep.dataforge.control.api.DeviceHub
 import hep.dataforge.meta.Meta
 import hep.dataforge.names.Name
+import hep.dataforge.names.NameToken
 import kotlin.reflect.KClass
 
 class DeviceManager : AbstractPlugin(), DeviceHub {
@@ -16,14 +17,14 @@ class DeviceManager : AbstractPlugin(), DeviceHub {
     /**
      * Actual list of connected devices
      */
-    private val top = HashMap<Name, Device>()
+    private val top = HashMap<NameToken, Device>()
-    override val devices: Map<Name, Device> get() = top
+    override val devices: Map<NameToken, Device> get() = top
 
     val controller by lazy {
         HubController(this, context)
     }
 
-    fun registerDevice(name: Name, device: Device) {
+    fun registerDevice(name: NameToken, device: Device) {
         top[name] = device
     }
 

dataforge-device-core/src/commonMain/kotlin/hep/dataforge/control/controllers/HubController.kt

@@ -1,9 +1,9 @@
 package hep.dataforge.control.controllers
 
-import hep.dataforge.control.api.Consumer
 import hep.dataforge.control.api.DeviceHub
 import hep.dataforge.control.api.DeviceListener
 import hep.dataforge.control.api.get
+import hep.dataforge.io.Consumer
 import hep.dataforge.io.Envelope
 import hep.dataforge.io.Responder
 import hep.dataforge.meta.MetaItem
@@ -11,6 +11,7 @@ import hep.dataforge.meta.get
 import hep.dataforge.meta.string
 import hep.dataforge.meta.wrap
 import hep.dataforge.names.Name
+import hep.dataforge.names.NameToken
 import hep.dataforge.names.toName
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.channels.Channel
@@ -38,7 +39,7 @@ class HubController(
         }
     }
 
-    private val listeners: Map<Name, DeviceListener> = hub.devices.mapValues { (name, device) ->
+    private val listeners: Map<NameToken, DeviceListener> = hub.devices.mapValues { (name, device) ->
         object : DeviceListener {
             override fun propertyChanged(propertyName: String, value: MetaItem<*>?) {
                 if (value == null) return
@@ -62,7 +63,7 @@ class HubController(
 
     suspend fun respondMessage(message: DeviceMessage): DeviceMessage = try {
         val targetName = message.target?.toName() ?: Name.EMPTY
-        val device = hub[targetName]
+        val device = hub[targetName] ?: error("The device with name $targetName not found in $hub")
         DeviceController.respondMessage(device, targetName.toString(), message)
     } catch (ex: Exception) {
         DeviceMessage.fail {
@@ -72,7 +73,7 @@ class HubController(
 
     override suspend fun respond(request: Envelope): Envelope = try {
         val targetName = request.meta[DeviceMessage.TARGET_KEY].string?.toName() ?: Name.EMPTY
-        val device = hub[targetName]
+        val device = hub[targetName] ?: error("The device with name $targetName not found in $hub")
         if (request.data == null) {
             DeviceController.respondMessage(device, targetName.toString(), DeviceMessage.wrap(request.meta)).wrap()
         } else {

dataforge-device-server/src/main/kotlin/hep/dataforge/control/server/deviceWebServer.kt

@@ -115,7 +115,7 @@ public fun Application.deviceModule(
                             +"Device server dashboard"
                         }
                         deviceNames.forEach { deviceName ->
-                            val device = manager[deviceName]
+                            val device = manager[deviceName] ?: error("The device with name $deviceName not found in $manager")
                             div {
                                 id = deviceName
                                 h2 { +deviceName }

demo/src/main/kotlin/hep/dataforge/control/demo/DemoDevice.kt

@@ -25,7 +25,7 @@ class DemoDevice(parentScope: CoroutineScope) : DeviceBase() {
         parentScope.coroutineContext + executor.asCoroutineDispatcher() + Job(parentScope.coroutineContext[Job])
     )
 
-    val timeScale: IsolatedDeviceProperty by writingVirtual(5000.0.asValue())
+    val timeScale: DeviceProperty by writingVirtual(5000.0.asValue())
     var timeScaleValue by timeScale.double()
 
     val sinScale by writingVirtual(1.0.asValue())

demo/src/main/kotlin/hep/dataforge/control/demo/demoDeviceServer.kt

@@ -5,7 +5,7 @@ import hep.dataforge.control.controllers.devices
 import hep.dataforge.control.server.startDeviceServer
 import hep.dataforge.control.server.whenStarted
 import hep.dataforge.meta.double
-import hep.dataforge.names.asName
+import hep.dataforge.names.NameToken
 import io.ktor.server.engine.ApplicationEngine
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
@@ -50,7 +50,7 @@ suspend fun Trace.updateXYFrom(flow: Flow<Iterable<Pair<Double, Double>>>) {
 
 
 fun startDemoDeviceServer(context: Context, device: DemoDevice): ApplicationEngine {
-    context.devices.registerDevice("demo".asName(), device)
+    context.devices.registerDevice(NameToken("demo"), device)
     val server = context.startDeviceServer(context.devices)
     server.whenStarted {
         plotlyModule("plots").apply {

motors/build.gradle.kts

@@ -5,7 +5,6 @@ plugins {
 
 //TODO to be moved to a separate project
 
-
 dependencies {
     implementation(project(":dataforge-device-core"))
 }

motors/src/main/kotlin/ru/mipt/npm/devices/pimotionmaster/PiMotionMasterDevice.kt

@@ -1,18 +1,25 @@
 package ru.mipt.npm.devices.pimotionmaster
 
-import hep.dataforge.control.base.DeviceBase
+import hep.dataforge.control.base.*
-import hep.dataforge.control.base.DeviceProperty
-import hep.dataforge.control.base.writingVirtual
 import hep.dataforge.control.ports.Port
 import hep.dataforge.control.ports.PortProxy
+import hep.dataforge.control.ports.send
 import hep.dataforge.control.ports.withDelimiter
 import hep.dataforge.meta.MetaItem
 import hep.dataforge.values.Null
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.takeWhile
+import kotlinx.coroutines.flow.toList
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+
+public class PiMotionMasterDevice(
+    parentScope: CoroutineScope,
+    private val portFactory: suspend (MetaItem<*>?) -> Port,
+) : DeviceBase() {
 
-class PiMotionMasterDevice(parentScope: CoroutineScope, val portFactory: suspend (MetaItem<*>?) -> Port) : DeviceBase() {
     override val scope: CoroutineScope = CoroutineScope(
         parentScope.coroutineContext + Job(parentScope.coroutineContext[Job])
     )
@@ -23,14 +30,81 @@ class PiMotionMasterDevice(parentScope: CoroutineScope, val portFactory: suspend
 
     private val connector = PortProxy { portFactory(port.value) }
 
-    private suspend fun readPhrase(command: String) {
+    private val mutex = Mutex()
-        connector.receiving().withDelimiter("\n").first { it.startsWith(command) }
+
+    private suspend fun sendCommand(command: String, vararg arguments: String) {
+        val joinedArguments = if (arguments.isEmpty()) {
+            ""
+        } else {
+            arguments.joinToString(prefix = " ", separator = " ", postfix = "")
+        }
+        val stringToSend = "$command$joinedArguments\n"
+        connector.send(stringToSend)
     }
 
-//
+    /**
-//    val firmwareVersion by reading {
+     * Send a synchronous request and receive a list of lines as a response
-//        connector.r
+     */
-//    }
+    private suspend fun request(command: String, vararg arguments: String): List<String> = mutex.withLock {
+        sendCommand(command, *arguments)
+        val phrases = connector.receiving().withDelimiter("\n")
+        return@withLock phrases.takeWhile { it.endsWith(" \n") }.toList() + phrases.first()
+    }
+
+    private suspend fun requestAndParse(command: String, vararg arguments: String): Map<String, String> = buildMap {
+        request(command, *arguments).forEach { line ->
+            val (key, value) = line.split("=")
+            put(key, value)
+        }
+    }
+
+    /**
+     * Send a synchronous command
+     */
+    private suspend fun send(command: String, vararg arguments: String) {
+        mutex.withLock {
+            sendCommand(command, *arguments)
+        }
+    }
+
+    public val initialize: Action by action {
+        send("INI")
+    }
+
+    public val firmwareVersion: ReadOnlyDeviceProperty by readingString {
+        request("VER?").first()
+    }
+
+    public inner class Axis(public val axisId: String) : DeviceBase() {
+        override val scope: CoroutineScope get() = this@PiMotionMasterDevice.scope
+        public val enabled: DeviceProperty by writingBoolean<Axis>(
+            getter = {
+                val result = requestAndParse("EAX?", axisId)[axisId]?.toIntOrNull()
+                    ?: error("Malformed response. Should include integer value for $axisId")
+                result != 0
+            },
+            setter = { oldValue, newValue ->
+                val value = if(newValue){
+                    "1"
+                } else {
+                    "0"
+                }
+                send("EAX", axisId, value)
+                oldValue
+            }
+        )
+
+        public val halt: Action by action {
+            send("HLT", axisId)
+        }
+    }
+
+    init {
+        //list everything here to ensure it is initialized
+        initialize
+        firmwareVersion
+
+    }
 
 
 }