bezel

Patterns / Agent

Composer

Markdown apps/gallery/src/patterns/agent.rs 

TextField::new(cx)
    .with_shape(Shape::Grow { min: 3, max: 12 })
    .with_key_context(COMPOSER_CONTEXT)
    .with_placeholder("Ask anything, or # to attach a file")

One library call on a card of Theme::card_glass_bg. enter sends and shift-enter breaks a line, through a key context of the field's own.

The mention picker

let anchor = self.field.read(cx).offset_bounds(hash, window)?;

popover::menu_at(
    "composer-mentions",
    gpui::point(anchor.left(), anchor.bottom() + px(4.0)),
    card,
    None,
)

The only thing this pattern had to invent — and it is popover::Filter, the combobox's own state, mounted at a caret instead of under a trigger.

Its trigger is a read of the text rather than a key handler: the # nearest behind the caret, if nothing since it has been whitespace. Typing, pasting, arrowing back into a word and deleting the # then all agree without being special-cased.

offset_bounds is the same measurement the IME candidate panel anchors to, so the menu follows the caret down as the box grows. What # offers is a Vec<SharedString> — the app searches its own store.

The source is at apps/gallery/src/patterns/agent.rs.

Composer