There is no free lunch in the world. Semantics determine the amount of information a language carries, and information determines the upper limit of optimization. In other words, if a language is faster than c++, then its semantics must be faster than. I guess they want to replicate the success of ts partially replacing js, but I'm not sure about this.
Beware 7 Las Vegas Hotels That Could Ruin Your Vacation FeelingVegas
