From bbf4e8304b50b6a972cacc6337d1aa283ccb83be Mon Sep 17 00:00:00 2001
From: HombreLaser <sebastian-440@live.com>
Date: Sat, 2 Apr 2022 11:54:14 -0600
Subject: Añadido código del parser
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---
 include/parser.hpp |  28 +++++++++++++
 parser.cpp         | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 include/parser.hpp
 create mode 100644 parser.cpp

diff --git a/include/parser.hpp b/include/parser.hpp
new file mode 100644
index 0000000..02471d8
--- /dev/null
+++ b/include/parser.hpp
@@ -0,0 +1,28 @@
+/* PIA - Lenguajes Modernos de Programación
+ * FACULTAD DE CIENCIAS FÍSICO MATEMÁTICAS
+ * Luis Sebastián Martínez Vega - LCC */
+
+#include <string>
+#include <vector>
+#include "lexer.hpp"
+#ifndef PARSER_H
+#define PARSER_H
+
+class Parser{
+private:
+  std::string text;
+  Lexer tokenizer;
+  void setText(std::string text);
+  void parseExpr();
+  void parsePrimeExpr();
+  void parseTerm();
+  void parsePrimeTerm();
+  void parsePower();
+  void parsePrimePower();
+  void parseFactor();
+  bool checkToken(); // Checa el token actual del lexer.
+public:
+  void parse(std::string expr);
+};
+
+#endif /* PARSER_H */
diff --git a/parser.cpp b/parser.cpp
new file mode 100644
index 0000000..8cba19e
--- /dev/null
+++ b/parser.cpp
@@ -0,0 +1,119 @@
+#include <string>
+#include "include/parser.hpp"
+#include "include/lexer.hpp"
+#include "include/exceptions.hpp"
+
+using std::string;
+
+void Parser::setText(string text){
+  tokenizer.setText(text); // Se prepara el lexer.
+}
+
+bool Parser::checkToken(){
+  if(tokenizer.getCurrentToken().type == nil)
+    return false;
+
+  return true;
+}
+
+void Parser::parse(string expr){
+  setText(expr);
+  parseExpr();
+}
+
+void Parser::parseExpr(){
+  parseTerm();
+  parsePrimeExpr();
+}
+
+void Parser::parsePrimeExpr(){
+  if(tokenizer.getCurrentToken().type == sum
+     || tokenizer.getCurrentToken().type == substraction)
+  {
+    tokenizer.nextToken();
+
+    if(!checkToken())
+      throw ParserException("Carácter inválido.");
+
+    parseTerm();
+    parsePrimeExpr();
+  }
+}
+
+void Parser::parseTerm(){
+  parsePower();
+  parsePrimeTerm();
+}
+
+void Parser::parsePrimeTerm(){
+  if(tokenizer.getCurrentToken().type == multiplication
+     || tokenizer.getCurrentToken().type == division)
+  {
+    tokenizer.nextToken();
+
+    if(!checkToken())
+      throw ParserException("Carácter inválido.");
+
+    parsePower();
+    parsePrimeTerm();
+  }
+}
+
+void Parser::parsePower(){
+  parseFactor();
+  parsePrimePower();
+}
+
+void Parser::parsePrimePower(){
+  if(tokenizer.getCurrentToken().type == power)
+  {
+    tokenizer.nextToken();
+
+    if(tokenizer.getCurrentToken().type != number)
+      throw ParserException("Sintaxis incorrecta.");
+
+    parsePrimePower();
+  }
+}
+
+void Parser::parseFactor(){
+  switch(tokenizer.getCurrentToken().type)
+  {
+  case substraction:
+    tokenizer.nextToken();
+    parseExpr();
+    break;
+  case left_parens:
+    tokenizer.nextToken();
+    parseExpr();
+
+    // Consumimos paréntesis derecho.
+    if(tokenizer.getCurrentToken().type != right_parens)
+      throw ParserException("Sintaxis incorrecta.");
+    break;
+  case function:
+    tokenizer.nextToken();
+
+    if(tokenizer.getCurrentToken().type != left_parens)
+      throw ParserException("Sintaxis incorrecta.");
+
+    parseExpr();
+
+    if(tokenizer.getCurrentToken().type != right_parens)
+      throw ParserException("Sintaxis incorrecta.");
+    
+    break;
+  case variable:
+    tokenizer.nextToken();
+    
+    break;
+  case number:
+    tokenizer.nextToken();
+
+    break;
+  default:
+    throw ParserException("Sintaxis incorrecta.");
+    
+    break;
+  }
+}
-- 
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