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ExpressionImpl.cpp
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ExpressionImpl.cpp
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#include "ExpressionImpl.h"
#include "exprtk/ExprtkExpression.h"
#include "exprtk/ExprtkParser.h"
#include <sstream>
struct ExpressionImplValues
{
exprtk::symbol_table mSymbolTable;
exprtk::expression mExpression;
};
ExpressionImpl::ExpressionImpl()
{
mValues = std::make_unique<ExpressionImplValues>();
mValues->mExpression.register_symbol_table(mValues->mSymbolTable);
}
ExpressionImpl::~ExpressionImpl() {}
void ExpressionImpl::deinit()
{
mValues->mExpression.release();
mValues->mSymbolTable.clear();
}
void ExpressionImpl::clearSymbols() { mValues->mSymbolTable.clear(); }
bool ExpressionImpl::addVariable(const std::string &name, double &value, bool isConstant)
{
return mValues->mSymbolTable.add_variable(name, value, isConstant);
}
bool ExpressionImpl::addConstant(const std::string &name, double value)
{
return mValues->mSymbolTable.add_constant(name, value);
}
bool ExpressionImpl::compile(const std::string &expression, std::string *errorsOut)
{
exprtk::parser parser;
if (!parser.compile(expression, mValues->mExpression)) {
if (errorsOut) {
std::stringstream ss;
ss << parser.error();
for (std::size_t i = 0; i < parser.error_count(); ++i) {
exprtk::parser_error::type error = parser.get_error(i);
ss << "\n";
ss << "Pos: " << error.token.position
<< ", Type: " << exprtk::parser_error::to_str(error.mode);
ss << ", Msg: " << error.diagnostic;
}
(*errorsOut) = ss.str();
}
return false;
}
if (errorsOut) {
errorsOut->clear();
}
return true;
}
double ExpressionImpl::value() { return mValues->mExpression.value(); }
std::optional<double> ExpressionImpl::calculate(const std::string &expression)
{
exprtk::expression expr;
exprtk::parser parser;
if (parser.compile(expression, expr)) {
return {expr.value()};
}
return std::nullopt;
}