4 files changed, 48 insertions, 43 deletions

diff --git a/src/nodes.cc b/src/nodes.cc
index bab7ff7..1ab1502 100644
--- a/src/nodes.cc
+++ b/src/nodes.cc
@@ -1,4 +1,5 @@
 #include "nodes.h"
+#include "utils.h"
 #include "exceptions.h"
 
 #include <cmath>
@@ -93,4 +94,19 @@ TokenType OperatorNode::getToken() {
 	return this->operator_;
 }
 
+ConstantNode::ConstantNode(std::string identifier):
+	identifier_(identifier) { }
+
+double ConstantNode::solve() {
+
+}
+
+NodeType ConstantNode::getType() {
+	return NodeType::CONSTANT;
+}
+
+std::string ConstantNode::print() {
+	return this->identifier_;
+}
+
 }
diff --git a/src/nodes.h b/src/nodes.h
index e90669c..6783f3d 100644
--- a/src/nodes.h
+++ b/src/nodes.h
@@ -3,13 +3,14 @@
 
 #include <string>
 
-#include "utils.h"
-
 namespace SimpleParser {
 
+enum class TokenType : int8_t;
+
 enum class NodeType {
 	OPERAND,
 	OPERATOR,
+	CONSTANT,
 };
 
 class Node {
@@ -50,6 +51,18 @@ class OperandNode: public Node {
 		double value_;
 };
 
+class ConstantNode: public Node {
+	public:
+		explicit ConstantNode(std::string);
+
+		virtual double solve();
+		virtual NodeType getType();
+		virtual std::string print();
+
+	private:
+		std::string identifier_;
+};
+
 }
 
 #endif  // PARSER_SRC_NODES_H_
diff --git a/src/tree.cc b/src/tree.cc
index e63b7b3..f6d2282 100644
--- a/src/tree.cc
+++ b/src/tree.cc
@@ -9,6 +9,14 @@
 
 namespace SimpleParser {
 
+Node* topNodeFrom(const std::stack<Node*>& stack) {
+	if ( !stack.empty() ) {
+		return stack.top();
+	} else {
+		throw operator_exception();
+	}
+}
+
 Tree::Tree(std::string term):
 	term_(term) {
 	this->root_node_ = this->buildTree(term);
@@ -72,21 +80,10 @@ std::string Tree::print() {
 	return out.str();
 }
 
-Node* Tree::addOperand(Node** place, double value) {
-	this->node_collection_.emplace_back(
-		new OperandNode(value)
-	);
-
-	if ( place != nullptr ) {
-		*place = this->node_collection_.back().get();
-	}
-
-	return this->node_collection_.back().get();
-}
-
-Node* Tree::addOperand(Node** place, std::string value) {
+template <typename NType, typename... Args>
+Node* Tree::addNode(Node** place, Args&&... args) {
 	this->node_collection_.emplace_back(
-		new OperandNode(value)
+		new NType(std::forward<Args>(args)...)
 	);
 
 	if ( place != nullptr ) {
@@ -96,26 +93,6 @@ Node* Tree::addOperand(Node** place, std::string value) {
 	return this->node_collection_.back().get();
 }
 
-Node* Tree::addOperator(Node** place, TokenType token) {
-	this->node_collection_.emplace_back(
-		new OperatorNode(token)
-	);
-
-	if ( place != nullptr ) {
-		*place = this->node_collection_.back().get();
-	}
-
-	return this->node_collection_.back().get();
-}
-
-Node* topNodeFrom(const std::stack<Node*>& stack) {
-	if ( !stack.empty() ) {
-		return stack.top();
-	} else {
-		throw operator_exception();
-	}
-}
-
 Node* Tree::buildTree(std::string term) {
 	std::stack<Node*> operandStack;
 	std::stack<Node*> operatorStack;
@@ -139,7 +116,7 @@ Node* Tree::buildTree(std::string term) {
 
 				if ( token > lastNode->getToken() ) {
 					operatorStack.push( 
-						this->addOperator(nullptr, token)
+						this->addNode<OperatorNode>(nullptr, token)
 					);
 				} else {
 					Node* currOperator = topNodeFrom(operatorStack);
@@ -157,7 +134,7 @@ Node* Tree::buildTree(std::string term) {
 				}
 			} else {
 				operatorStack.push(
-					this->addOperator(nullptr, token)
+					this->addNode<OperatorNode>(nullptr, token)
 				);
 			}
 		} else {
@@ -171,14 +148,14 @@ Node* Tree::buildTree(std::string term) {
 						convertStream >> value;
 
 						operandStack.push(
-							this->addOperand(nullptr,value)
+							this->addNode<OperandNode>(nullptr, value)
 						);
 
 						break;
 					}
 					case TokenType::VALUE_IDENTIFIER: {
 						operandStack.push(
-							this->addOperand(nullptr,tmpLexer[0])
+							this->addNode<ConstantNode>(nullptr, tmpLexer[0])
 						);
 
 						break;
diff --git a/src/tree.h b/src/tree.h
index 858d737..68a31c1 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -17,9 +17,8 @@ class Tree {
 		std::string print();
 
 	private:
-		Node* addOperand(Node**, double);
-		Node* addOperand(Node**, std::string);
-		Node* addOperator(Node**, TokenType);
+		template <class NType, typename... Args>
+		Node* addNode(Node**, Args&&... args);
 		Node* buildTree(std::string);
 
 		std::vector<std::unique_ptr<Node>> node_collection_;