Syntax highlighting and editor support, create tree-sitter grammar
There are already some examples in the examples directory but more examples are always welcome!
unprint() function that removes the last printed text from stdout (all printed values are collected in the output list in the interpreter)
Implement proper rules to determine the equality of two functions
Make built-ins like join also return partially applied functions instead of raising errors if not enough arguments were given. You can also just use _ placeholders but this would be more intuitive and similar in behavior to user-defined functions.
The interpreter also recognizes binary, pre-parsed NumFu files, usually with the extension .nfut, which are generated by the numfu parse command. However, they cannot be imported as modules yet, which would be a great feature to add.