the source code for the OS demo is not "regular" code, it's full of `emiRelu`... https://github.com/chenglou/handwired/blob/main/src/handwire...
The main site & readme seem to overclaim, while the docs say things like "With Handwired you write a numeric program" and "No tool converts existing JavaScript source into a program" - https://github.com/chenglou/handwired/tree/main/docs
happy to be proven wrong, to have misunderstood this, etc.