1 files changed, 18 insertions, 18 deletions
diff --git a/include/simplifier.hpp b/include/simplifier.hpp
index dcc3225..e08f951 100644
--- a/include/simplifier.hpp
+++ b/include/simplifier.hpp
@@ -8,25 +8,25 @@
 
 class Simplifier {
 private:
-  void simplifyChildren(Expression *root, Expression *left, Expression *right);
-  Expression *ruleEval(Expression *expr);
-  Expression *ruleMultiplyByOne(MultiplicationExpression *expr);
-  Expression *ruleDivideByOne(DivisionExpression *expr);
-  Expression *ruleMultiplyByZero(MultiplicationExpression *expr);
-  Expression *ruleZeroDivision(DivisionExpression *expr);
-  Expression *ruleOnePower(PowerExpression *expr);
-  Expression *ruleZeroPower(PowerExpression *expr);
-  Expression *addZero(AddExpression *expr);
+  void simplifyChildren(Expression *root, Expression **left, Expression **right) const;
+  Expression *ruleEval(Expression *expr) const;
+  Expression *ruleMultiplyByOne(MultiplicationExpression *expr) const;
+  Expression *ruleDivideByOne(DivisionExpression *expr) const;
+  Expression *ruleMultiplyByZero(MultiplicationExpression *expr) const;
+  Expression *ruleZeroDivision(DivisionExpression *expr) const;
+  Expression *ruleOnePower(PowerExpression *expr) const;
+  Expression *ruleZeroPower(PowerExpression *expr) const;
+  Expression *addSubstractZero(Expression *expr) const;
 public:
-  Expression *visit(Variable *expr);
-  Expression *visit(Literal *expr);
-  Expression *visit(Function *expr);
-  Expression *visit(NegationExpression *expr);
-  Expression *visit(AddExpression *expr);
-  Expression *visit(SubExpression *expr);
-  Expression *visit(MultiplicationExpression *expr);
-  Expression *visit(DivisionExpression *expr);
-  Expression *visit(PowerExpression *expr);
+  Expression *visit(Variable *expr) const;
+  Expression *visit(Literal *expr) const;
+  Expression *visit(Function *expr) const;
+  Expression *visit(NegationExpression *expr) const;
+  Expression *visit(AddExpression *expr) const;
+  Expression *visit(SubExpression *expr) const;
+  Expression *visit(MultiplicationExpression *expr) const;
+  Expression *visit(DivisionExpression *expr) const;
+  Expression *visit(PowerExpression *expr) const;
 };
 
 Expression *simplify(Expression *to_simplify);