From 7750c4ec459469ec9a3781c22b0e0a2f6e4b2cf0 Mon Sep 17 00:00:00 2001
From: Karol Stasiak <karol.m.stasiak@gmail.com>
Date: Tue, 7 Aug 2018 17:36:14 +0200
Subject: [PATCH] Optimize constants of form (B+A)-B

---
 src/main/scala/millfork/env/Constant.scala | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/scala/millfork/env/Constant.scala b/src/main/scala/millfork/env/Constant.scala
index a5097b0b..eaa6d5f1 100644
--- a/src/main/scala/millfork/env/Constant.scala
+++ b/src/main/scala/millfork/env/Constant.scala
@@ -263,6 +263,8 @@ case class CompoundConstant(operator: MathOperator.Value, lhs: Constant, rhs: Co
         } else {
           CompoundConstant(MathOperator.Minus, a, rr - ll).quickSimplify
         }
+      case (CompoundConstant(MathOperator.Plus, a, ll@NumericConstant(lv, _)), b) if operator == MathOperator.Minus && a == b =>
+        ll.quickSimplify
       case (CompoundConstant(MathOperator.Minus, a, ll@NumericConstant(lv, _)), rr@NumericConstant(rv, _)) if operator == MathOperator.Plus =>
         if (lv >= rv) {
           CompoundConstant(MathOperator.Minus, a, ll - rr).quickSimplify