Use the `#:when` keyword instead of `when` to reduce loop body indentation.

Internal definitions are recommended instead of `let` expressions, to reduce nesting.

The `define` form supports a shorthand for defining functions.

Use `make-temporary-directory` to make directories instead of `make-temporary-file`.

`cond` with internal definitions is preferred over `if` with `let`, to reduce nesting

Specify a line mode of `'any` with `read-line` to avoid differences between Windows and other platforms.