refactor: address code review feedback

- Replace Vec::from_iter with .collect() (idiomatic)
- Simplify parse_key_list_from_option to plain for loop
- Clean up debugging comment in test
- Add test for multi-list priority order
- Clarify PermissiveHold wording in docs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: malpern

docs/config.adoc

@@ -2076,7 +2076,8 @@ This is useful for home row mods where fast typing should not trigger modifiers.
 Options are: `(tap-on-press <keys...>)` activates `$tap-action` early if a listed key is pressed;
 `(tap-on-press-release <keys...>)` activates `$tap-action` early if a listed key is pressed then released;
 `(hold-on-press <keys...>)` activates `$hold-action` early if a listed key is pressed.
-For any other key, activates `$hold-action` when the key is pressed and released (PermissiveHold behavior).
+For any other key: if that key is pressed and released while this key is waiting,
+`$hold-action` is triggered early (PermissiveHold behavior).
 All list options are optional.
 
 | `tap-hold-opposite-hand`

parser/src/cfg/custom_tap_hold.rs

@@ -140,15 +140,16 @@ pub(crate) fn custom_tap_hold_keys(
     keys_hold_on_press: &[OsCode],
     a: &Allocations,
 ) -> &'static CustomTapHoldFn {
-    let keys_tap_on_press = a.sref_vec(Vec::from_iter(
-        keys_tap_on_press.iter().copied().map(u16::from),
-    ));
-    let keys_tap_on_press_release = a.sref_vec(Vec::from_iter(
-        keys_tap_on_press_release.iter().copied().map(u16::from),
-    ));
-    let keys_hold_on_press = a.sref_vec(Vec::from_iter(
-        keys_hold_on_press.iter().copied().map(u16::from),
-    ));
+    let keys_tap_on_press = a.sref_vec(keys_tap_on_press.iter().copied().map(u16::from).collect());
+    let keys_tap_on_press_release = a.sref_vec(
+        keys_tap_on_press_release
+            .iter()
+            .copied()
+            .map(u16::from)
+            .collect(),
+    );
+    let keys_hold_on_press =
+        a.sref_vec(keys_hold_on_press.iter().copied().map(u16::from).collect());
     a.sref(
         move |mut queued: QueuedIter, _coord: KCoord| -> (Option<WaitingAction>, bool) {
             while let Some(q) = queued.next() {

parser/src/cfg/tap_hold.rs

@@ -427,18 +427,15 @@ fn parse_key_list_from_option(
             kw
         );
     }
-    option[1..].iter().try_fold(vec![], |mut keys, key| {
-        key.atom(s.vars())
-            .map(|a| -> Result<()> {
-                keys.push(
-                    str_to_oscode(a)
-                        .ok_or_else(|| anyhow_expr!(key, "string of a known key is expected"))?,
-                );
-                Ok(())
-            })
-            .ok_or_else(|| {
-                anyhow_expr!(key, "string of a known key is expected, found list instead")
-            })??;
-        Ok(keys)
-    })
+    let mut keys = Vec::new();
+    for key in &option[1..] {
+        let a = key.atom(s.vars()).ok_or_else(|| {
+            anyhow_expr!(key, "string of a known key is expected, found list instead")
+        })?;
+        keys.push(
+            str_to_oscode(a)
+                .ok_or_else(|| anyhow_expr!(key, "string of a known key is expected"))?,
+        );
+    }
+    Ok(keys)
 }

src/tests/sim_tests/tap_hold_tests.rs

@@ -169,11 +169,8 @@ fn tap_hold_keys_tap_on_press_release() {
     // tap-on-press-release key needs press+release to trigger tap
     let result = simulate(cfg, "d:a t:20 d:b u:b t:100").to_ascii();
     assert_eq!("t:20ms dn:X t:6ms dn:B t:1ms up:B", result);
-    // tap-on-press-release key pressed but not released: no early decision,
-    // falls through to PermissiveHold which triggers hold on press+release
-    // Wait, it IS in tap-on-press-release list so it checks for release.
-    // If not released, falls through to PermissiveHold check which also needs release.
-    // So just pressing without releasing: no decision until timeout.
+    // tap-on-press-release key pressed but not released: no early tap or hold,
+    // waits for timeout.
     let result = simulate(cfg, "d:a t:20 d:b t:200").to_ascii();
     assert_eq!("t:100ms dn:Y t:1ms dn:B", result);
 }
@@ -241,6 +238,23 @@ fn tap_hold_keys_no_options() {
     assert_eq!("t:100ms dn:Y t:50ms up:Y", result);
 }
 
+#[test]
+fn tap_hold_keys_priority_order() {
+    // When a key appears in multiple lists, tap-on-press wins over hold-on-press.
+    let cfg = "
+        (defsrc a b)
+        (deflayer l1
+         (tap-hold-keys 100 100 x y
+           (tap-on-press b)
+           (hold-on-press b))
+         b
+        )
+    ";
+    // b is in both lists; tap-on-press should win → triggers tap
+    let result = simulate(cfg, "d:a t:20 d:b t:100").to_ascii();
+    assert_eq!("t:20ms dn:X t:6ms dn:B", result);
+}
+
 #[test]
 fn tap_hold_release_keys() {
     let cfg = "