Implement the lexer.
Add support for comments in the lexer.
Implement the parser grammar.
Add rule for parsing ifs.
Bootstrap the runtime.
Compute 1 + 2 using the runtime API.
Implement the interpreter.
Eval an IfNode.
Implement while & < operator.
Implement JS compiler.
Compile if to js.
Implment bytecode compiler.
Compile else body of the if and compile get_local.
Simplify interpreter.

Move constants from Runtime to Constants.
Rename Runtime as an eval context to RootContext.
Split local getting into Get/SetLocal node and rule.
Prep code for live coding.