Added some optimizations

libraries/lepton/src/ParsedExpression.cpp

@@ -167,6 +167,16 @@ ExpressionTreeNode ParsedExpression::substituteSimplerExpression(const Expressio
                     return ExpressionTreeNode(new Operation::MultiplyConstant(second*dynamic_cast<const Operation::MultiplyConstant*>(&children[0].getOperation())->getValue()), children[0].getChildren()[0]);
                 return ExpressionTreeNode(new Operation::MultiplyConstant(second), children[0]);
             }
+            if (children[0].getOperation().getId() == Operation::NEGATE && children[1].getOperation().getId() == Operation::NEGATE) // The two negations cancel
+                return ExpressionTreeNode(new Operation::Multiply(), children[0].getChildren()[0], children[1].getChildren()[0]);
+            if (children[0].getOperation().getId() == Operation::NEGATE && children[1].getOperation().getId() == Operation::MULTIPLY_CONSTANT) // Negate the constant
+                return ExpressionTreeNode(new Operation::Multiply(), children[0].getChildren()[0], ExpressionTreeNode(new Operation::MultiplyConstant(-dynamic_cast<const Operation::MultiplyConstant*>(&children[1].getOperation())->getValue()), children[1].getChildren()[0]));
+            if (children[1].getOperation().getId() == Operation::NEGATE && children[0].getOperation().getId() == Operation::MULTIPLY_CONSTANT) // Negate the constant
+                return ExpressionTreeNode(new Operation::Multiply(), ExpressionTreeNode(new Operation::MultiplyConstant(-dynamic_cast<const Operation::MultiplyConstant*>(&children[0].getOperation())->getValue()), children[0].getChildren()[0]), children[1].getChildren()[0]);
+            if (children[0].getOperation().getId() == Operation::NEGATE) // Pull the negation out so it can possibly be optimized further
+                return ExpressionTreeNode(new Operation::Negate(), ExpressionTreeNode(new Operation::Multiply(), children[0].getChildren()[0], children[1]));
+            if (children[1].getOperation().getId() == Operation::NEGATE) // Pull the negation out so it can possibly be optimized further
+                return ExpressionTreeNode(new Operation::Negate(), ExpressionTreeNode(new Operation::Multiply(), children[0], children[1].getChildren()[0]));
             break;
         }
         case Operation::DIVIDE:
@@ -184,6 +194,14 @@ ExpressionTreeNode ParsedExpression::substituteSimplerExpression(const Expressio
                     return ExpressionTreeNode(new Operation::MultiplyConstant(dynamic_cast<const Operation::MultiplyConstant*>(&children[0].getOperation())->getValue()/denominator), children[0].getChildren()[0]);
                 return ExpressionTreeNode(new Operation::MultiplyConstant(1.0/denominator), children[0]); // Replace a divide with a multiply
             }
+            if (children[0].getOperation().getId() == Operation::NEGATE && children[1].getOperation().getId() == Operation::NEGATE) // The two negations cancel
+                return ExpressionTreeNode(new Operation::Divide(), children[0].getChildren()[0], children[1].getChildren()[0]);
+            if (children[1].getOperation().getId() == Operation::NEGATE && children[0].getOperation().getId() == Operation::MULTIPLY_CONSTANT) // Negate the constant
+                return ExpressionTreeNode(new Operation::Divide(), ExpressionTreeNode(new Operation::MultiplyConstant(-dynamic_cast<const Operation::MultiplyConstant*>(&children[0].getOperation())->getValue()), children[0].getChildren()[0]), children[1].getChildren()[0]);
+            if (children[0].getOperation().getId() == Operation::NEGATE) // Pull the negation out so it can possibly be optimized further
+                return ExpressionTreeNode(new Operation::Negate(), ExpressionTreeNode(new Operation::Divide(), children[0].getChildren()[0], children[1]));
+            if (children[1].getOperation().getId() == Operation::NEGATE) // Pull the negation out so it can possibly be optimized further
+                return ExpressionTreeNode(new Operation::Negate(), ExpressionTreeNode(new Operation::Divide(), children[0], children[1].getChildren()[0]));
             break;
         }
         case Operation::POWER:
@@ -216,6 +234,8 @@ ExpressionTreeNode ParsedExpression::substituteSimplerExpression(const Expressio
                 return ExpressionTreeNode(new Operation::MultiplyConstant(-dynamic_cast<const Operation::MultiplyConstant*>(&children[0].getOperation())->getValue()), children[0].getChildren()[0]);
             if (children[0].getOperation().getId() == Operation::CONSTANT) // Negate a constant
                 return ExpressionTreeNode(new Operation::Constant(-getConstantValue(children[0])));
+            if (children[0].getOperation().getId() == Operation::NEGATE) // The two negations cancel
+                return children[0].getChildren()[0];
             break;
         }
         case Operation::MULTIPLY_CONSTANT:
@@ -224,6 +244,8 @@ ExpressionTreeNode ParsedExpression::substituteSimplerExpression(const Expressio
                 return ExpressionTreeNode(new Operation::MultiplyConstant(dynamic_cast<const Operation::MultiplyConstant*>(&node.getOperation())->getValue()*dynamic_cast<const Operation::MultiplyConstant*>(&children[0].getOperation())->getValue()), children[0].getChildren()[0]);
             if (children[0].getOperation().getId() == Operation::CONSTANT) // Multiply two constants
                 return ExpressionTreeNode(new Operation::Constant(dynamic_cast<const Operation::MultiplyConstant*>(&node.getOperation())->getValue()*getConstantValue(children[0])));
+            if (children[0].getOperation().getId() == Operation::NEGATE) // Combine a multiply and a negate into a single multiply
+                return ExpressionTreeNode(new Operation::MultiplyConstant(-dynamic_cast<const Operation::MultiplyConstant*>(&node.getOperation())->getValue()), children[0].getChildren()[0]);
         }
     }
     return ExpressionTreeNode(node.getOperation().clone(), children);

tests/TestParser.cpp

@@ -178,6 +178,12 @@ int main() {
         verifyEvaluation("2*(3*x)", 4.0, 4.0, 24.0);
         verifyEvaluation("2*x/3", 1.0, 4.0, 2.0/3.0);
         verifyEvaluation("x*2/3", 1.0, 4.0, 2.0/3.0);
+        verifyEvaluation("5*(-x)*(-y)", 1.0, 4.0, 20.0);
+        verifyEvaluation("5*(-x)*(y)", 1.0, 4.0, -20.0);
+        verifyEvaluation("5*(x)*(-y)", 1.0, 4.0, -20.0);
+        verifyEvaluation("5*(-x)/(-y)", 1.0, 4.0, 1.25);
+        verifyEvaluation("5*(-x)/(y)", 1.0, 4.0, -1.25);
+        verifyEvaluation("5*(x)/(-y)", 1.0, 4.0, -1.25);
         verifyEvaluation("x*w; w = 5", 3.0, 1.0, 15.0);
         verifyEvaluation("a+b^2;a=x-b;b=3*y", 2.0, 3.0, 74.0);
         verifyInvalidExpression("1..2");