From 7000eaf5a271646ade1a5920f11f9549bb571473 Mon Sep 17 00:00:00 2001
From: Danilo Pianini <danilo.pianini@unibo.it>
Date: Mon, 14 Nov 2016 19:23:33 +0100
Subject: [PATCH] Implement nbrDelay and nbrLag

---
 .../alchemist/protelis/AlchemistExecutionContext.java    | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/alchemist/alchemist-incarnation-protelis/src/main/java/it/unibo/alchemist/protelis/AlchemistExecutionContext.java b/alchemist/alchemist-incarnation-protelis/src/main/java/it/unibo/alchemist/protelis/AlchemistExecutionContext.java
index 15650b5d1f..6963953078 100644
--- a/alchemist/alchemist-incarnation-protelis/src/main/java/it/unibo/alchemist/protelis/AlchemistExecutionContext.java
+++ b/alchemist/alchemist-incarnation-protelis/src/main/java/it/unibo/alchemist/protelis/AlchemistExecutionContext.java
@@ -203,7 +203,14 @@ public ExecutionEnvironment getExecutionEnvironment() {
 
     @Override
     public Field nbrLag() {
-        return buildField(Functions.identity(), 0);
+        return buildField(time -> getCurrentTime().doubleValue() - time, getCurrentTime().doubleValue());
+    }
+
+    /**
+     * @return The same behavior of MIT Proto's nbrdelay (forward view).
+     */
+    public Field nbrDelay() {
+        return buildField(Functions.identity(), getDeltaTime());
     }
 
     @Override