Prune commentary and stale Rust port notes

app-rust/src/ui/tap.rs

@@ -1,27 +1,7 @@
-//! A tap on something in the transcript, and holding the reader's edge
-//! while what they tapped changes height.
-//!
-//! Both halves are shared by everything in the transcript that opens: a
-//! tool card and its group ([`crate::ui::tool`]), and a message's "Show all"
-//! ([`crate::ui::row`]). They are here rather than in either of those because
-//! there is one right answer to "was that a tap?" on this screen, and two
-//! copies of it would eventually disagree -- which on a scrolling screen
-//! means one of them firing at the end of a pan.
-
 use crate::ui::selection::Selection;
 use iris::prelude::*;
 use std::{cell::RefCell, rc::Rc};
 
-/// Register `f` as `ptr`'s **tap**, panning the list instead when the
-/// finger moves.
-///
-/// `Selection::drag` with no row is the same call `row.rs` makes with one:
-/// it drives the shared `DragArbiter`, so a drag starting on a card
-/// scrolls (and flings) the transcript exactly as one starting on a
-/// paragraph does, and only a press that committed to nothing comes back
-/// as `Tapped`. A bare `CursorSense::click()` would be a second,
-/// disagreeing detector -- it fires at the end of a pan too, so every
-/// scroll that began on a card would also toggle it.
 pub(crate) fn on_tap<Rsc: HasEvents>(
     rsc: &mut Rsc,
     ptr: WeakWidget<WidgetPtr>,
@@ -31,9 +11,6 @@ pub(crate) fn on_tap<Rsc: HasEvents>(
 ) where
     Rsc::State: FocusHost + OpenUrl,
 {
-    // The whole `drag_senses()` set -- what any widget driving a
-    // `DragGesture` registers, `Cancel` included. See `row.rs`'s twin
-    // registration for what leaving `Cancel` out did.
     ptr.on(CursorSense::drag_senses(), move |ctx, rsc| {
         let outcome = selection.borrow_mut().drag(
             rsc,
@@ -51,29 +28,7 @@ pub(crate) fn on_tap<Rsc: HasEvents>(
     .add(rsc);
 }
 
-/// Hold the edge the reader is looking at while row `key` changes height.
-///
-/// `LazySpan::note_tap` wants a viewport-relative position and a row only
-/// knows its own box, so `LazySpan::extent` (last frame's on-screen box
-/// for this key) turns the two into the position `lazy_span.rs`'s
-/// hold-the-edge pass resolves against -- the two-step contract that
-/// module's doc describes for `AGENTS.md`'s `holdTopEdge`.
-///
-/// Call it **before** the change, from every handler that makes a row
-/// taller or shorter: opening a card, opening a group, asking for the
-/// whole of a capped block or message. A handler that skips it is one
-/// where the transcript jumps under the reader's finger.
 pub(crate) fn hold_edge(rsc: &mut impl UiRsc, list: WeakWidget<LazySpan>, key: RowKey) {
-    // Only when the list actually has an extent for this row. `None`
-    // means the row has not been drawn yet -- which happens the moment
-    // something opens a group before the first frame
-    // (`TranscriptScreen::expand_tail_tools`, the headless screenshot) --
-    // and standing in `0.0` for it tells the layout pass to hold an edge
-    // at the top of the viewport that nothing was ever at. The whole list
-    // then places itself against that invented anchor: rows drawn at each
-    // other's cached heights, tool cards as empty bars with their text a
-    // group's height below them (`docs/bench/p1b-2026-09-06/`'s first
-    // attempt). Nothing to hold is not the same as an edge at zero.
     if let Some((top, _bottom)) = list(rsc).extent(key) {
         list(rsc).note_tap(top);
     }