2 files changed, 70 insertions, 1 deletions
diff --git a/src/include/parser.hpp b/src/include/parser.hpp
index 7bc7997..1399943 100644
--- a/src/include/parser.hpp
+++ b/src/include/parser.hpp
@@ -5,12 +5,18 @@
  * PrimeTerm --> (*|/)Term | Null
  * Factor --> -Expression | (Expression) | operand */
 #pragma once
+#include <string>
 #include "tokenizer.hpp"
 #include "syntax_tree.hpp"
 
 
 class Parser {
 private:
+  // Private attributes.
+  Tokenizer tokenizer = Tokenizer();
+  Token **tokens;
+  Token *current_token;
+  // End of private attributes.
   // Private methods.
   void parseExpression();
   void parsePrimeExpression();
@@ -20,5 +26,5 @@ private:
   // End of private methods.
 public:
   Parser();
-  const SyntaxTree *parse();
+  const SyntaxTree *parse(const std::string &input);
 };
diff --git a/src/parser.cpp b/src/parser.cpp
new file mode 100644
index 0000000..68c2297
--- /dev/null
+++ b/src/parser.cpp
@@ -0,0 +1,63 @@
+#include <string>
+#include "include/tokenizer.hpp"
+#include "include/syntax_tree.hpp"
+#include "include/parser.hpp"
+
+const SyntaxTree *Parser::parse(const std::string &input) {
+  tokens = tokenizer.tokenize(input);
+  current_token = tokens[0];
+  
+  return nullptr;
+}
+
+void Parser::parseExpression() {
+  parseTerm();
+  parsePrimeExpression();
+}
+
+void Parser::parsePrimeExpression() {
+  if(current_token->type == nil)
+    return;
+
+  if(current_token->type == sum || current_token->type == substraction) {
+    ++current_token;
+    parseExpression();
+  }
+}
+
+void Parser::parseTerm() {
+  parseFactor();
+  parsePrimeTerm();
+}
+
+void Parser::parsePrimeTerm() {
+  if(current_token->type == nil)
+    return;
+
+  if(current_token->type == multiplication ||
+     current_token->value == division) {
+    ++current_token;
+    parseTerm();
+  }
+}
+
+void Parser::parseFactor() {
+  switch(current_token->type) {
+  case substraction:
+    ++current_token;
+    parseExpression();
+    break;
+  case left_parens:
+    ++current_token;
+    parseExpression();
+    if(current_token->type != right_parens)
+      return;
+    ++current_token;
+    break;
+  case operand:
+    ++current_token;
+    break;
+  default:
+    return;
+  }
+}