Simplify branch-return.
Simplify read escape.
Add lexer match function.
Fix escape sequence bug.
Remove extra newline.
Combine lexer unrecognized character errors.
Remove default case from lexer main switch.
Remove isWhitespace.
Remove extra call to substr.
Refactor keyword search.
Convert radix exception to assertion.
Combine string reading methods.
Add comments to lexer.
Refactor to remove useless advance calls.
Remove isDigit function.
Fix string allocation error.
Clean up number scanning.