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#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();
/* Si no se ha consumido toda la cadena, lanzamos
error. */
if(tokenizer.getCurrentToken().type != nil)
throw ParserException("Sintaxis incorrecta.");
}
void Parser::parseExpr(){
parseTerm();
parsePrimeExpr();
}
void Parser::parsePrimeExpr(){
if(tokenizer.getCurrentToken().type == sum
|| tokenizer.getCurrentToken().type == substraction)
{
tokenizer.nextToken();
if(!checkToken())
throw ParserException("Sintaxis incorrecta.");
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("Sintaxis incorrecta.");
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.");
tokenizer.nextToken();
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.");
tokenizer.nextToken();
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.");
tokenizer.nextToken();
break;
case variable:
tokenizer.nextToken();
break;
case number:
tokenizer.nextToken();
break;
default:
throw ParserException("Sintaxis incorrecta.");
break;
}
}
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