- [ ]   Parentheses for expressions
- [ ]   Logical operators (and, or, not)
- [ ]   ELSE IF and ELSE
- [ ]   FOR loop
- [ ]   Number literals written in binary, hex, and octal
- [ ]   Better compiler errors (e.g., what line the error occurred)
- [ ]   Allow multiple code files
- [ ]   Functions with parameters and return values
- [ ]   Lexical scope (see [scope](https://en.wikipedia.org/wiki/Scope_(computer_science)))
- [ ]   Standard library (e.g., file operations)
- [ ]   [Abstract syntax tree](https://en.wikipedia.org/wiki/Abstract_syntax_tree) representation
- [ ]   More primitive types (e.g., integer, strings, boolean)
- [ ]   Arrays
- [ ]   Record types (i.e., structs or tuples)
- [ ]   Type checking (see [type systems](https://en.wikipedia.org/wiki/Type_system))
- [ ]   Compiler optimizations (e.g., [constant folding](https://en.wikipedia.org/wiki/Constant_folding))
- [ ]   Test cases for the compiler (see [unit testing](https://en.wikipedia.org/wiki/Unit_testing) and [test-driven development](https://en.wikipedia.org/wiki/Test-driven_development))