From 76935afa8ac8f86237888fe63475ed9827f15570 Mon Sep 17 00:00:00 2001
From: Kirill Shumilov <brusher.designer@gmail.com>
Date: Fri, 23 Nov 2018 17:53:09 +0300
Subject: [PATCH] fix(xod/core): fix `xod/core/delta` to work just like before
 adding pulses into tabtests

---
 workspace/__lib__/xod/core/delta/patch.cpp     |  9 +++++----
 .../__lib__/xod/core/delta/patch.test.tsv      | 18 +++++++++---------
 workspace/__lib__/xod/core/delta/patch.xodp    | 10 +++++-----
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/workspace/__lib__/xod/core/delta/patch.cpp b/workspace/__lib__/xod/core/delta/patch.cpp
index cc4f44e7..9fccc80c 100644
--- a/workspace/__lib__/xod/core/delta/patch.cpp
+++ b/workspace/__lib__/xod/core/delta/patch.cpp
@@ -12,15 +12,16 @@ void evaluate(Context ctx) {
     auto inValue = getValue<input_IN>(ctx);
 
     if (isInputDirty<input_RST>(ctx)) {
-        state->refValue = 0;
-        emitValue<output_OUT>(ctx, inValue);
+        state->refValue = inValue;
+        emitValue<output_OUT>(ctx, 0);
         return;
     }
 
-    if (isInputDirty<input_REF>(ctx)) {
-        state->refValue = inValue;
+    if (!isInputDirty<input_UPD>(ctx)) {
+      return;
     }
 
     auto outValue = inValue - state->refValue;
     emitValue<output_OUT>(ctx, outValue);
+    state->refValue = inValue;
 }
diff --git a/workspace/__lib__/xod/core/delta/patch.test.tsv b/workspace/__lib__/xod/core/delta/patch.test.tsv
index 99c1b7a6..33ec8b9f 100644
--- a/workspace/__lib__/xod/core/delta/patch.test.tsv
+++ b/workspace/__lib__/xod/core/delta/patch.test.tsv
@@ -1,10 +1,10 @@
-IN	BIAS	RST	OUT
+IN	UPD	RST	OUT
 0	no-pulse	no-pulse	0
-10	pulse	no-pulse	0
-30	no-pulse	no-pulse	20
-0	no-pulse	no-pulse	-10
-20	no-pulse	pulse	20
-10	no-pulse	no-pulse	10
-10	pulse	no-pulse	0
-10	pulse	pulse	10
-50	no-pulse	no-pulse	50
+10	pulse	no-pulse	10
+30	no-pulse	no-pulse	10
+20	no-pulse	pulse	0
+30	pulse	no-pulse	10
+50	pulse	no-pulse	20
+10	pulse	no-pulse	-40
+10	pulse	pulse	0
+5	pulse	no-pulse	-5
diff --git a/workspace/__lib__/xod/core/delta/patch.xodp b/workspace/__lib__/xod/core/delta/patch.xodp
index b6708a5e..d89c4129 100644
--- a/workspace/__lib__/xod/core/delta/patch.xodp
+++ b/workspace/__lib__/xod/core/delta/patch.xodp
@@ -1,5 +1,5 @@
 {
-  "description": "Outputs a difference between the current `IN` value and its reference value.",
+  "description": "Calculates difference between current and past input values.",
   "nodes": [
     {
       "id": "HyJCAXqNG",
@@ -10,9 +10,9 @@
       "type": "xod/patch-nodes/not-implemented-in-xod"
     },
     {
-      "description": "Triggers memoization of the input value as the reference value.",
+      "description": "Update: trigger a calculation and store the current `IN` value as the new “past” value.",
       "id": "S1bhCQqVM",
-      "label": "REF",
+      "label": "UPD",
       "position": {
         "x": 102,
         "y": 0
@@ -20,7 +20,7 @@
       "type": "xod/patch-nodes/input-pulse"
     },
     {
-      "description": "The difference between `IN` and the reference value which was stored when `REF` received a pulse. Can be positive or negative. Always equals to 0 on the first update.",
+      "description": "The last difference value.",
       "id": "SkFpRm9Nz",
       "position": {
         "x": 34,
@@ -29,7 +29,7 @@
       "type": "xod/patch-nodes/output-number"
     },
     {
-      "description": "Resets the reference value to 0.",
+      "description": "Resets the stored past value to the current input value. Efficiently sets `OUT` to 0.",
       "id": "SyYn0X5NM",
       "label": "RST",
       "position": {