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Tokenizer.cpp
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Tokenizer.cpp
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#include "include/Tokenizer.hpp"
#include "include/ParserException.hpp"
// Constructor
Tokenizer::Tokenizer(string s)
{
_type = token::OTHER;
_s = s;
_pos = 0;
_d = 0;
}
// Separate the next token from the string and increment _pos depending on the length of each token
string Tokenizer::nextToken()
{
string s;
token::TokenType currentType = stringType();
switch (currentType)
{
case token::OPERAND: {
unsigned int dot_num = 0;
// parse before the letter that is not a valid operand
//this works now we have to search for dots.
int j = _s.find_first_not_of(operands, _pos);
//search for the occurance of .. here.
std::string dot = _s.substr(_pos, j - _pos);
for (size_t i = 0; i < dot.size(); i++)
{
if (dot[i] == '.')
{
dot_num++;
}
}
if (dot_num > 1)
{
throw INVALIDOPERAND("Input a valid operand");
}
std::cout<<dot<<std::endl;
s.assign(_s, _pos, j - _pos);
convertToNumber(s);
_pos += j - _pos;
break;
}
// For operator, as it only has one character, so parse only one character out of the next string
//if the previous terms are also an operator we need to think about it.
case token::OPERATOR: {
s.assign(_s, _pos, 1);
_pos++;
break;
}
// For left bracket, as it only has one character, so parse only one character out of the next string
case token::LEFTBRACKET: {
s.assign("(");
_pos++;
break;
}
// For right bracket, as it only has one character, so parse only one character out of the next string
case token::RIGHTBRACKET: {
s.assign(")");
_pos++;
break;
}
// For string that contains letters, it can be a function or a variable. We parse the substring
case token::LETTER: {
// j is the last position in the substring that is not a letter
int j = _s.find_first_not_of(letters, _pos);
s.assign(_s, _pos, j - _pos);
// then Convert the substring with letters into appropriate types
_type = convertToOtherTypes(s);
_pos += j - _pos;
break;
}
case token::OTHER:
break;
default:
break;
}
return s;
}
// Convert a string to a number
void Tokenizer::convertToNumber(string s)
{
_d = stod(s);
}
// Convert letter type string to appropriate token types
token::TokenType Tokenizer::convertToOtherTypes(string s)
{
if (s == "x" || s == "y")
_type = token::VARIABLE;
else if (s == "sin" || s == "cos" || s == "tan" || s == "cot" || s == "sec" || s == "csc" || s == "ln" || s == "exp" || s == "min" || s == "max")
_type = token::FUNCTION;
else
{
throw INVALIDFORMAT("Invalid funtion or variable name.");
}
return _type;
}
// Get number from the conversion from a double type
double Tokenizer::getNumber()
{
return _d;
}
// Get the type of the current parsed string
token::TokenType Tokenizer::getType()
{
return _type;
}
// Categorize the type of string being parsed currently, by checking if character at a given position fits the characters in the private constant strings
token::TokenType Tokenizer::stringType()
{
int operand_pos = operands.find(_s[_pos]);
int operator_pos = operators.find(_s[_pos]);
int left_pos = left.find(_s[_pos]);
int right_pos = right.find(_s[_pos]);
int letter_pos = letters.find(_s[_pos]);
//-1 is the resutl if nothing is found
if (operand_pos != -1)
_type = token::OPERAND;
else if (operator_pos != -1)
_type = token::OPERATOR;
else if (left_pos != -1)
_type = token::LEFTBRACKET;
else if (right_pos != -1)
_type = token::RIGHTBRACKET;
else if (letter_pos != -1)
_type = token::LETTER;
return _type;
}
// Check if there is any string to parse
bool Tokenizer::isEmpty()
{
if (static_cast<int>(_pos) < 0)
{
return true;
}
return static_cast<int>(_pos) >= static_cast<int>(_s.length());
}