form: How text is colored

In duat, the way text is styled is through Forms. The Form struct, alongside the form module, are imported by the prelude:

#![allow(unused)]
fn main() {
setup_duat!(setup);
use duat::prelude::*;

fn setup() {
    // Setting by Form
    form::set("punctuation.bracket", Form::red());
    form::set("default", Form::with("#575279").on("#faf4ed"));
    form::set("matched_pair", Form::blue().underlined()); 
    
    // Setting by reference
    form::set("accent.debug", "default.debug");
}
}

The main function that you will use from this module is form::set. This function sets the form with the given name on the left to the argument on the right. This argument can be of two types:

• A Form argument will just modify the named form to be shown like that;
• A &str argument will "reference" the form on the right. If the form on the right is altered, so will the one on the left. This reduces the need for setting a ton of forms in things like colorschemes;

How forms should be named

Every form in duat should be named like this: [a-z0-9]+(\.[a-z0-9]+)*. That way, inheritance of forms becomes very predictable, and it's much easier for plugin writers to depend on that feature.

There is one exception to this rule however, that being the defaut form. The default form, unlike other forms, can have Widget specific implementations, like default.StatusLine, which will change the default form only on StatusLines, and is set by default.

Colorschemes

The other main function that you will use from this module is the form::set_colorscheme function. This function will change the colorscheme to a previously named one:

#![allow(unused)]
fn main() {
setup_duat!(setup);
use duat::prelude::*;
use catppuccin::Catppuccin;

fn setup() {
    // Adds four colorschemes, "catppuccin-latte" among them.
    plug!(Catppuccin::new());
    
    form::set_colorscheme("catppuccin-latte");
}
}

Form inheritance

Another aspect of duat's forms that can save a lot of typing is the concept of Form inheritance. In Duat, forms follow the following structure:

• If form.subform is unset, it will reference form;
• If form.subform is set to Form::green(), it won't be changed when form changes, staying at Form::green();
• If form.subform is set to reference other_form, changing other_form will also change form.subform, but changing form won't;

As a consequence of this, for example, if you were to set the markup form to something, every form with a name like markup.* that isn't already set, would follow the change to the markup form.

Additionally, if the form f0.f1.f2 is set to something, the forms f0 and f1.f2 would also be set, although they will reference the default form in that situation, not whatever f0.f1.f2 was set to.

Masks

A mask is essentially the opposite of the inheritance concept. Instead of the longer form inheriting from the shorter forms, the shorter forms will be mapped for longer ones.

It works like this: Say I have a File widget, and in it, there are instances of the function form, used to highlight function identifiers. If there is a function.error form, and I tell the File to use the error mask, instead of using the function form, Duat will use function.error.

In duat, by default there are four masks: error, warning, info, and inactive. The first three are used primarily to show color coded notifications. The last one is unused, but you can use it to change how unfocused files should be displayed.

You can also add more masks through form::enable_mask. If you want to learn more about masks and how to use them, you should check out the masks chapter