prompt: If submitting empty prompt, use default (last used)

helix-core/src/register.rs

@@ -69,6 +69,10 @@ impl Registers {
         self.get(name).map(|reg| reg.read())
     }
 
+    pub fn first(&self, name: char) -> Option<&String> {
+        self.read(name).and_then(|entries| entries.first())
+    }
+
     pub fn inner(&self) -> &HashMap<char, Register> {
         &self.inner
     }

helix-term/src/commands.rs

@@ -1488,7 +1488,7 @@ fn select_regex(cx: &mut Context) {
         Some(reg),
         ui::completers::none,
         move |view, doc, regex, event| {
-            if event != PromptEvent::Update {
+            if !matches!(event, PromptEvent::Update | PromptEvent::Validate) {
                 return;
             }
             let text = doc.text().slice(..);
@@ -1509,7 +1509,7 @@ fn split_selection(cx: &mut Context) {
         Some(reg),
         ui::completers::none,
         move |view, doc, regex, event| {
-            if event != PromptEvent::Update {
+            if !matches!(event, PromptEvent::Update | PromptEvent::Validate) {
                 return;
             }
             let text = doc.text().slice(..);
@@ -1657,7 +1657,7 @@ fn searcher(cx: &mut Context, direction: Direction) {
                 .collect()
         },
         move |view, doc, regex, event| {
-            if event != PromptEvent::Update {
+            if !matches!(event, PromptEvent::Update | PromptEvent::Validate) {
                 return;
             }
             search_impl(
@@ -3563,7 +3563,7 @@ fn keep_or_remove_selections_impl(cx: &mut Context, remove: bool) {
         Some(reg),
         ui::completers::none,
         move |view, doc, regex, event| {
-            if event != PromptEvent::Update {
+            if !matches!(event, PromptEvent::Update | PromptEvent::Validate) {
                 return;
             }
             let text = doc.text().slice(..);

helix-term/src/ui/mod.rs

@@ -63,18 +63,8 @@ pub fn regex_prompt(
                     doc.set_selection(view.id, snapshot.clone());
                     view.offset = offset_snapshot;
                 }
-                PromptEvent::Validate => match Regex::new(input) {
-                    Ok(regex) => {
-                        let (view, doc) = current!(cx.editor);
-                        // Equivalent to push_jump to store selection just before jump
-                        view.jumps.push((doc_id, snapshot.clone()));
-                        fun(view, doc, regex, event);
-                    }
-                    Err(_err) => (), // TODO: mark command line as error
-                },
-
-                PromptEvent::Update => {
-                    // skip empty input, TODO: trigger default
+                PromptEvent::Update | PromptEvent::Validate => {
+                    // skip empty input
                     if input.is_empty() {
                         return;
                     }
@@ -96,6 +86,11 @@ pub fn regex_prompt(
                             // revert state to what it was before the last update
                             doc.set_selection(view.id, snapshot.clone());
 
+                            if event == PromptEvent::Validate {
+                                // Equivalent to push_jump to store selection just before jump
+                                view.jumps.push((doc_id, snapshot.clone()));
+                            }
+
                             fun(view, doc, regex, event);
 
                             view.ensure_cursor_in_view(doc, config.scrolloff);

helix-term/src/ui/prompt.rs

@@ -442,10 +442,21 @@ impl Prompt {
         let line = area.height - 1;
         // render buffer text
         surface.set_string(area.x, area.y + line, &self.prompt, prompt_color);
+
+        let input: Cow<str> = if self.line.is_empty() {
+            // latest value in the register list
+            self.history_register
+                .and_then(|reg| cx.editor.registers.first(reg).cloned()) // TODO: can we avoid cloning?
+                .map(|entry| entry.into())
+                .unwrap_or_else(|| Cow::from(""))
+        } else {
+            self.line.as_str().into()
+        };
+
         surface.set_string(
             area.x + self.prompt.len() as u16,
             area.y + line,
-            &self.line,
+            &input,
             prompt_color,
         );
     }
@@ -510,7 +521,18 @@ impl Component for Prompt {
                     self.recalculate_completion(cx.editor);
                     self.exit_selection();
                 } else {
-                    (self.callback_fn)(cx, &self.line, PromptEvent::Validate);
+                    // handle executing with last command in history if nothing entered
+                    let input: Cow<str> = if self.line.is_empty() {
+                        // latest value in the register list
+                        self.history_register
+                            .and_then(|reg| cx.editor.registers.first(reg).cloned())
+                            .map(|entry| entry.into())
+                            .unwrap_or_else(|| Cow::from(""))
+                    } else {
+                        self.line.as_str().into()
+                    };
+
+                    (self.callback_fn)(cx, &input, PromptEvent::Validate);
 
                     if let Some(register) = self.history_register {
                         // store in history