multiple onConnect in sessions support

src/commonMain/kotlin/net/sergeych/kiloparsec/KiloClient.kt

@@ -156,8 +156,19 @@ class KiloClient<S>(
             var secretIdKey: SigningKey? = null
 
             /**
-             * Build local command implementations (remotely callable ones), exception
+             * Build local command implementations, those callable from the server, exception
-             * class handlers, etc.
+             * class handlers, and anything else [KiloInterface] allows. Usage sample:
+             * 
+             * ```kotlin
+             * val client = KiloClient {
+             *     connect { connectTcpDevice("localhost:$port") }
+             *     local {
+             *         on(cmdPing) {
+             *             "pong! $it"
+             *         }
+             *     }
+             * }
+             * ```
              */
             fun local(f: KiloInterface<S>.() -> Unit) {
                 interfaceBuilder = f

src/commonMain/kotlin/net/sergeych/kiloparsec/KiloClientConnection.kt

@@ -80,7 +80,7 @@ class KiloClientConnection<S>(
                 kiloRemoteInterface.complete(
                     KiloRemoteInterface(deferredParams, clientInterface)
                 )
-                clientInterface.onConnectHandler?.invoke(params.scope)
+                clientInterface.onConnectHandlers.invokeAll(params.scope)
                 onConnectedStateChanged?.invoke(true)
                 job.join()
 
@@ -104,4 +104,7 @@ class KiloClientConnection<S>(
     override suspend fun <A> push(cmd: Command<A, Unit>, args: A) {
         kiloRemoteInterface.await().push(cmd, args)
     }
-}
+}
+
+internal fun <S>Collection<KiloHandler<S>>.invokeAll(scope: KiloScope<S>) =
+    forEach { runCatching { scope.it() } }

src/commonMain/kotlin/net/sergeych/kiloparsec/KiloInterface.kt

@@ -1,5 +1,6 @@
 package net.sergeych.kiloparsec
 
+typealias KiloHandler<S> = KiloScope<S>.()->Unit
 /**
  * The local interface to provide functions, register errors for Kiloparsec users. Use it
  * with [KiloClient], [KiloClientConnection], [KiloServerConnection], etc.
@@ -14,9 +15,16 @@ package net.sergeych.kiloparsec
  */
 open class KiloInterface<S> : LocalInterface<KiloScope<S>>() {
 
-    internal var onConnectHandler: (KiloScope<S>.()->Unit) ? = null
+    internal val onConnectHandlers = mutableListOf<KiloHandler<S>>()
 
-    fun onConnected(f: KiloScope<S>.()->Unit) { onConnectHandler = f }
+    /**
+     * Registers handler [f] for [onConnected] event, to the head or the end of handler list.
+     *
+     * @param addFirst if true, [f] will be added to the beginning of the list of handlers
+     */
+    fun onConnected(addFirst: Boolean = false, f: KiloScope<S>.()->Unit) {
+        if( addFirst ) onConnectHandlers.add(0, f) else  onConnectHandlers += f
+    }
 
     init {
         registerError { RemoteInterface.UnknownCommand(it) }

src/commonMain/kotlin/net/sergeych/kiloparsec/KiloServerConnection.kt

@@ -75,7 +75,7 @@ class KiloServerConnection<S>(
                 kiloRemoteInterface.complete(
                     KiloRemoteInterface(deferredParams, clientInterface)
                 )
-                clientInterface.onConnectHandler?.invoke(p.scope)
+                clientInterface.onConnectHandlers.invokeAll(p.scope)
             }
         }
 

src/ktorSocketTest/kotlin/net/sergeych/kiloparsec/adapter/InternetTest.kt

@@ -26,9 +26,11 @@ class InternetTest {
         val cmdSave by command<String, Unit>()
         val cmdLoad by command<Unit, String>()
         val cmdDrop by command<Unit, Unit>()
+        val cmdPing by command<String, String>()
         val cmdException by command<Unit, Unit>()
+        val cmdCallClient by command<String, String>()
 
-        val cli = KiloInterface<Session>().apply {
+        val serverInterface = KiloInterface<Session>().apply {
             registerError { TestException() }
             onConnected { session.data = "start" }
             on(cmdSave) { session.data = it }
@@ -41,18 +43,26 @@ class InternetTest {
             on(cmdDrop) {
                 throw LocalInterface.BreakConnectionException()
             }
+            on(cmdCallClient) {
+                remote.call(cmdPing, it)
+            }
         }
-        val server = KiloServer(cli, acceptTcpDevice(port)) {
+        val server = KiloServer(serverInterface, acceptTcpDevice(port)) {
             Session("unknown")
         }
 
         data class LocalSession(val localFoo: String)
 
         val client = KiloClient {
-            addErrors(cli)
+            addErrors(serverInterface)
             session { LocalSession("unknown") }
             // TODO: add register error variant
             connect { connectTcpDevice("localhost:$port") }
+            local {
+                on(cmdPing) {
+                    "pong! $it"
+                }
+            }
         }
 
         assertEquals("start", client.call(cmdLoad))
@@ -68,7 +78,7 @@ class InternetTest {
 
         // reconnect?
         assertEquals("start", client.call(cmdLoad))
-
+        assertEquals("pong! 42", client.call(cmdCallClient, "42"))
         server.close()
     }