Succesively uncover code

Since Typst has great builtin support for typesetting code, Polylux wants to provide a convenience feature for this as well. Namely, the function #reveal-code takes a code block and splits it into parts shown on different subslides.

As an example:

#reveal-code(lines: (1, 3, 6, 7))[```rust
  pub fn main() {
    let x = vec![3, 4, 1];
    let y = &x;
    if let Some(a) = x.first() {
      dbg!(a);
    } else {
      println!("x is empty.");
    }
  }
```]

As we can see, the code is revealed up to the first, third, sixth, and then seventh row on each new subslide. Every line that has already been previously revealed is shown in gray. Afterwards, the whole code is shown without alterations.

Configuration

You can configure a couple of things about reveal-code:

Show the whole code in the end

As demonstrated above, this is the default behaviour. If you don't want that, use the option full: false like so:

#reveal-code(lines: (2, 4), full: false)[```
  first line
  second line
  third line
  fourth line
  fifth line
```]

What to do with previous and future lines

By default, previously uncovered lines are shown in gray and not yet uncovered lines are hidden. This can be controlled using the before and after options. Like the cover mode for other functions, these accept either hide or any color. The default is thus before: gray and after: hide.

First subslide

Similar to here, there is also a start option to specify the first subslide where code is revealed.