Añadido código del lexer

1 files changed, 99 insertions, 5 deletions

diff --git a/lexer.cpp b/lexer.cpp
index c58ebb5..9cfb2f7 100644
--- a/lexer.cpp
+++ b/lexer.cpp
@@ -3,18 +3,112 @@
  * Luis Sebastián Martínez Vega - LCC */
 
 #include <string>
+#include <cctype>
 #include "include/lexer.hpp"
+#include "include/exceptions.hpp"
 
-Lexer::Lexer(std::string text){
-  this->text = text;
+using std::string, std::isalpha, std::isdigit;
+
+Lexer::Lexer(string text): current_token(nil, {}){
+  setText(text);
 }
 
-void Lexer::setCurrentToken(Token val){
-  current_token = val;
+void Lexer::setText(string text){
+  this->text = text;
+  // Inicializamos el lexer.
+  current_token = nextToken();
+  var_name = '\0';
 }
 
 Token Lexer::getCurrentToken(){
   return current_token;
 }
 
-void Lexer::nextToken(){}
+bool Lexer::matchFunction(string function_name){
+  string name = text.substr(current_char, 2);
+  bool matched = name == function_name;
+
+  // Si hubo una coincidencia movemos el puntero.
+  if(matched)
+    current_char += 3;
+
+  return matched;
+}
+
+string Lexer::createNumber(){
+  string number;
+
+  while(isdigit(text[current_char]) && current_char < text.length())
+  {
+    number += text[current_char];
+    ++current_char;
+  }
+
+  return number;
+}
+
+Token Lexer::match(){
+  // Probamos las funciones.
+  if(current_char + 2 < text.length())
+  {
+    if(matchFunction("sin"))
+      return Token(function, "sin");
+    else if(matchFunction("cos"))
+      return Token(function, "cos");
+    else if(matchFunction("tan"))
+      return Token(function, "tan");
+    else if(matchFunction("csc"))
+      return Token(function, "csc");
+    else if(matchFunction("sec"))
+      return Token(function, "ctg");
+  }
+  
+  if(isdigit(text[current_char]))
+    return Token(number, createNumber());
+
+  if(isalpha(text[current_char]))
+  {
+    /* Si es la primera vez que se lee un token variable o
+       si la variable leída es igual a la anteriormente leída. */
+    if(var_name == '\0' || var_name == text[current_char])
+      return Token(variable, string(1, var_name));
+
+    // Error, se introdujo una expresión con dos o más variables.
+    throw LexerException("Encontrada más de una variable.");
+  }
+
+  /* El token actual no es ni una variable, número o función.
+     Ahora a probar operadores. */
+  switch(text[current_char])
+  {
+  case '+':
+    ++current_char;
+    return Token(sum, {});
+  case '-':
+    ++current_char;
+    return Token(substraction, {});
+  case '*':
+    ++current_char;
+    return Token(multiplication, {});
+  case '/':
+    ++current_char;
+    return Token(division, {});
+  case '^':
+    ++current_char;
+    return Token(power, {});
+  case '(':
+    ++current_char;
+    return Token(left_parens, {});
+  case ')':
+    ++current_char;
+    return Token(right_parens, {});
+  default:
+    throw LexerException("Carácter inválido.");
+  }
+}
+
+Token Lexer::nextToken(){
+  current_token = match();
+  
+  return current_token;
+}