expression_evaluation.cpp

#include <ECF_base.h>
#include "expression_evaluation.h"
namespace utility{
    double evaluateExpression(const std::map<std::string,double>& variables, std::string expression)
    {
        std::stack<std::string> operators;
        std::stack<double> values;
        std::vector<std::string> splitsContainer;
        boost::split(splitsContainer,expression,boost::is_any_of(" "));
        for(uint i = 0; i < splitsContainer.size(); i++) {
            if(existingOperators.count(splitsContainer[i])) {
                operators.push(splitsContainer[i]);
            }
            else if(variables.find(splitsContainer[i]) != variables.end()) {
                values.push(variables.at(splitsContainer[i]));
            }
            else if(splitsContainer[i] == "(") {
                continue;
            }
            else if(splitsContainer[i] == ")") {
                if(operators.empty()) {
                    break;
                }
                std::string op = operators.top();
                operators.pop();
                double numericalV = values.top();
                values.pop();
                if(op == "+") {
                    numericalV = values.top() + numericalV;
                    values.pop();
                }
                else if(op == "-") {
                    numericalV = values.top() - numericalV;
                    values.pop();
                }
                else if(op == "*") {
                    numericalV = values.top() * numericalV;
                    values.pop();
                }
                else if(op == "/") {
                    numericalV = values.top() / numericalV;
                    values.pop();
                }
                else if(op == "^") {
                    numericalV = std::pow(values.top(), numericalV);
                    values.pop();
                }
                else if(op == "max") {
                    numericalV = std::max(values.top(),numericalV);
                    values.pop();
                }
                else if(op == "min") {
                    numericalV = std::min(values.top(),numericalV);
                    values.pop();
                }
                else if(op == "sin") {
                    numericalV = std::sin(numericalV);
                }
                else if(op == "cos") {
                    numericalV = std::cos(numericalV);
                }
                else if(op == "sqrt") {
                    numericalV = std::sqrt(numericalV);
                }
                else if(op == "ln") {
                    numericalV = std::log(numericalV);
                }
                values.push(numericalV);
            }
            else {
                double numericalV;
                try{
                    numericalV = str2dbl(splitsContainer[i]);
                    values.push(numericalV);
                }catch(std::exception& ex) {
                    std::cerr << "Nešto nije u redu. Nisam mogao obraditi: " << splitsContainer[i] << '\n';
                }
            }
        }
        return values.top();
    }
}