From 909727ade856e31ecb20ee281fe81cc4cfa21e53 Mon Sep 17 00:00:00 2001
From: Eivind Kvedalen <eivind@kvedalen.name>
Date: Mon, 28 Mar 2016 00:38:35 +0200
Subject: [PATCH] Expressions: Fixed parsing of unit expressions similar to
 1/unit.

---
 src/App/Expression.cpp | 14 ++++++++++++++
 src/App/Expression.h   |  6 ++++++
 2 files changed, 20 insertions(+)

diff --git a/src/App/Expression.cpp b/src/App/Expression.cpp
index eee2b4a58..15e7e7d0e 100644
--- a/src/App/Expression.cpp
+++ b/src/App/Expression.cpp
@@ -1833,6 +1833,20 @@ UnitExpression * ExpressionParser::parseUnit(const App::DocumentObject *owner, c
 
     // Simplify expression
     Expression * simplified = ScanResult->simplify();
+
+    if (!unitExpression) {
+        OperatorExpression * fraction = freecad_dynamic_cast<OperatorExpression>(ScanResult);
+
+        if (fraction && fraction->getOperator() == OperatorExpression::DIV) {
+            NumberExpression * nom = freecad_dynamic_cast<NumberExpression>(fraction->getLeft());
+            UnitExpression * denom = freecad_dynamic_cast<UnitExpression>(fraction->getRight());
+            const double epsilon = std::numeric_limits<double>::epsilon();
+
+            // If not initially a unit expression, but value is equal to 1, it means the expression is something like 1/unit
+            if (denom && nom && essentiallyEqual(nom->getValue(), 1.0, epsilon))
+                unitExpression = true;
+        }
+    }
     delete ScanResult;
 
     if (unitExpression) {
diff --git a/src/App/Expression.h b/src/App/Expression.h
index 1f78daf68..e4528e223 100644
--- a/src/App/Expression.h
+++ b/src/App/Expression.h
@@ -246,6 +246,12 @@ public:
 
     virtual void visit(ExpressionVisitor & v);
 
+    Operator getOperator() const { return op; }
+
+    Expression * getLeft() const { return left; }
+
+    Expression * getRight() const { return right; }
+
 protected:
     Operator op;        /**< Operator working on left and right */
     Expression * left;  /**< Left operand */