MoonScript -> JavaScript
This is a new transformer and compiler for MoonScript that targets JavaScript. It is an experiment to test tableshape as a way to rewrite the MoonScript to Lua transformer. Using tableshape will make it easier to develop new features and generate optimized code at the expense of compiling slower compared to the hand written transformer MoonScript currently uses. (Hopefully the performance penalty is not significant)
In the current MoonScript implementation, the transformer and compiler run at the same time. State about the code, like what variables are declared, are stored in the compiler. When the compiler compiles a line, it can set state for the transfer to see on the next line it processes.
In this new approach, the compiler and transformer are completely separate steps. The compiler is responsible for translating a subset of syntax nodes to to the target language code with no state. The transformer will run completely ahead of time and keep track of all state as it transforms the syntax tree.
This approach should help clean up some of the more problematic nodes in MoonScript, like the "Run" node. The syntax tree will go back to a plain table tree with no special instanced nodes that have compiler state in them.
Why JavaScript
It's not clear if this project will result in a fully functional JavaScript alternative. MoonScript has a lot of Lua semantics built into its syntax that will not map well to JavaScript. It is not a goal of this project to change any of MoonScript's syntax to be more compatible with JavaScript.
It will allow you to compile a subset of the MoonScript syntax to JavaScript, giving you the opportunity to write shared code across browser and server.
Hopefully this can be used to write Lapis views that can be used in JavaScript.