var fps = 1 / (time_frame / 16);
// You divide by 16 because time_frame gets multiplied by 16
// And you use time_frame because time_step doesn't always contain the time the last frame needed to render
About your second question, no, there is no way to use the content of a cstring as code! engine_getscript() simply returns the pointer to the function with the given name, that you can then invoke. However, I would use something different since calling engine_getscript() every keystroke is probably pretty slow.
