Write some amount of documentation

src/app.rs

@@ -281,6 +281,45 @@ impl App {
         self.project_state.mark_dirty(change.bank, change.pattern);
     }
 
+    pub fn execute_script_oneshot(
+        &self,
+        script: &str,
+        link: &LinkState,
+        audio_tx: &arc_swap::ArcSwap<Sender<crate::engine::AudioCommand>>,
+    ) -> Result<(), String> {
+        let (bank, pattern) = self.current_bank_pattern();
+        let step_idx = self.editor_ctx.step;
+        let speed = self
+            .project_state
+            .project
+            .pattern_at(bank, pattern)
+            .speed
+            .multiplier();
+
+        let ctx = StepContext {
+            step: step_idx,
+            beat: link.beat(),
+            bank,
+            pattern,
+            tempo: link.tempo(),
+            phase: link.phase(),
+            slot: 0,
+            runs: 0,
+            iter: 0,
+            speed,
+            fill: false,
+            nudge_secs: 0.0,
+        };
+
+        let cmds = self.script_engine.evaluate(script, &ctx)?;
+        for cmd in cmds {
+            let _ = audio_tx
+                .load()
+                .send(crate::engine::AudioCommand::Evaluate { cmd, time: None });
+        }
+        Ok(())
+    }
+
     pub fn compile_current_step(&mut self, link: &LinkState) {
         let step_idx = self.editor_ctx.step;
         let (bank, pattern) = self.current_bank_pattern();
@@ -1117,12 +1156,20 @@ impl App {
             AppCommand::PageDown => self.page.down(),
 
             // Help navigation
-            AppCommand::HelpNextTopic => {
-                self.ui.help_topic = (self.ui.help_topic + 1) % help_view::topic_count();
+            AppCommand::HelpToggleFocus => {
+                use crate::state::HelpFocus;
+                self.ui.help_focus = match self.ui.help_focus {
+                    HelpFocus::Topics => HelpFocus::Content,
+                    HelpFocus::Content => HelpFocus::Topics,
+                };
             }
-            AppCommand::HelpPrevTopic => {
+            AppCommand::HelpNextTopic(n) => {
                 let count = help_view::topic_count();
-                self.ui.help_topic = (self.ui.help_topic + count - 1) % count;
+                self.ui.help_topic = (self.ui.help_topic + n) % count;
+            }
+            AppCommand::HelpPrevTopic(n) => {
+                let count = help_view::topic_count();
+                self.ui.help_topic = (self.ui.help_topic + count - (n % count)) % count;
             }
             AppCommand::HelpScrollDown(n) => {
                 let s = self.ui.help_scroll_mut();