README.md
qme
Question mark expression just as C/C++'s
Overview
Compile once and execute any times with different values of the variables in the question mark expression. Recursion is used during the whole compilation and execution, so please carefully control the number of variables in your question mark expressions, and enlage the size of the stack if inevitable, or use qme::O0/qme::O1 to compile it, qme::safe_execute to execute it and qme::safe_delete to delete it, then no recursion will be introduced (except question mark expression used as sub expression).
Quick start
Execute make or make debug, then execute ./test_question_exp
Example:
auto cb = [](const std::map<std::string, float>& dm, const std::string& variable_name) {
auto iter = dm.find(variable_name);
if (iter == std::end(dm))
throw("undefined symbol " + variable_name);
return iter->second;
};
std::map<std::string, float> dm_1;
dm_1["a"] = -100.f;
dm_1["b"] = 1.f;
dm_1["c"] = 11.f;
auto cb_1 = [&](const std::string& variable_name) {return cb(dm_1, variable_name);};
auto exp = qme::compiler<>::compile<>("a > 0 ? b > 0 ? b : 100 : c + 1");
if (exp)
{
puts("perform the question mark expression:");
try {printf("%f\n", (*exp)(cb_1));}
catch (const std::exception& e) {puts(e.what());}
catch (const std::string& e) {puts(e.data());}
catch (const char* e) {puts(e);}
catch (...) {puts("unknown exception happened!");}
}Compiler requirement:
Visual C++ 11.0, GCC 4.7 or Clang 3.1 at least, with c++11 features;