Merge pull request #97 from Microsoft/startup_delay

Startup delay for sensors to get values

libs/core/input.ts

@@ -13,6 +13,7 @@ namespace sensors.internal {
 
         control.runInBackground(() => {
             let prev = query()
+            changeHandler(prev, prev)
             while (true) {
                 loops.pause(periodMs)
                 let curr = query()

libs/core/linux.cpp

@@ -393,6 +393,10 @@ static void runPoller(Thread *thr) {
     // note that this is run without the user mutex held - it should not modify any state!
     TValue prev = pxt::runAction0(query);
 
+    startUser();
+    pxt::runAction2(thr->act, prev, prev);
+    stopUser();
+
     while (true) {
         sleep_core_us(us);
         if (paniced)

libs/ev3/pxt.json

@@ -3,7 +3,8 @@
     "description": "The EV3 library",
     "files": [
         "README.md",
-        "ns.ts"
+        "ns.ts",
+        "startup.ts"
     ],
     "dependencies": {
         "base": "file:../base",

libs/ev3/startup.ts

@@ -0,0 +1,4 @@
+// This is the last thing executed before user code
+
+// We pause for 100ms to give time to read sensor values, so they work in on_start block
+loops.pause(100)