add completions for search and global search

helix-term/src/commands.rs

@@ -1072,6 +1072,7 @@ fn select_regex(cx: &mut Context) {
         cx,
         "select:".into(),
         Some(reg),
+        |_input: &str| Vec::new(),
         move |view, doc, regex, event| {
             if event != PromptEvent::Update {
                 return;
@@ -1094,6 +1095,7 @@ fn split_selection(cx: &mut Context) {
         cx,
         "split:".into(),
         Some(reg),
+        |_input: &str| Vec::new(),
         move |view, doc, regex, event| {
             if event != PromptEvent::Update {
                 return;
@@ -1154,6 +1156,22 @@ fn search_impl(doc: &mut Document, view: &mut View, contents: &str, regex: &Rege
     };
 }
 
+fn search_completions(cx: &mut Context) -> Vec<String> {
+    let count = cx.count();
+    let (view, doc) = current!(cx.editor);
+    let text = doc.text().slice(..);
+
+    let selection = doc.selection(view.id).clone().transform(|range| {
+        textobject::textobject_word(text, range, textobject::TextObject::Inside, count)
+    });
+
+    selection
+        .ranges()
+        .iter()
+        .map(|range| text.slice(range.from()..range.to()).to_string())
+        .collect::<Vec<String>>()
+}
+
 // TODO: use one function for search vs extend
 fn search(cx: &mut Context) {
     let reg = cx.register.unwrap_or('/');
@@ -1164,11 +1182,19 @@ fn search(cx: &mut Context) {
     // HAXX: sadly we can't avoid allocating a single string for the whole buffer since we can't
     // feed chunks into the regex yet
     let contents = doc.text().slice(..).to_string();
+    let completions = search_completions(cx);
 
     let prompt = ui::regex_prompt(
         cx,
         "search:".into(),
         Some(reg),
+        move |input: &str| {
+            completions
+                .iter()
+                .filter(|comp| comp.starts_with(input))
+                .map(|comp| (0.., std::borrow::Cow::Owned(comp.clone())))
+                .collect()
+        },
         move |view, doc, regex, event| {
             if event != PromptEvent::Update {
                 return;
@@ -1228,10 +1254,19 @@ fn global_search(cx: &mut Context) {
     let (all_matches_sx, all_matches_rx) =
         tokio::sync::mpsc::unbounded_channel::<(usize, PathBuf)>();
     let smart_case = cx.editor.config.smart_case;
+
+    let completions = search_completions(cx);
     let prompt = ui::regex_prompt(
         cx,
         "global search:".into(),
         None,
+        move |input: &str| {
+            completions
+                .iter()
+                .filter(|comp| comp.starts_with(input))
+                .map(|comp| (0.., std::borrow::Cow::Owned(comp.clone())))
+                .collect()
+        },
         move |_view, _doc, regex, event| {
             if event != PromptEvent::Validate {
                 return;
@@ -4013,6 +4048,7 @@ fn keep_selections(cx: &mut Context) {
         cx,
         "keep:".into(),
         Some(reg),
+        |_input: &str| Vec::new(),
         move |view, doc, regex, event| {
             if event != PromptEvent::Update {
                 return;

helix-term/src/ui/mod.rs

@@ -29,6 +29,7 @@ pub fn regex_prompt(
     cx: &mut crate::commands::Context,
     prompt: std::borrow::Cow<'static, str>,
     history_register: Option<char>,
+    completion_fn: impl FnMut(&str) -> Vec<prompt::Completion> + 'static,
     fun: impl Fn(&mut View, &mut Document, Regex, PromptEvent) + 'static,
 ) -> Prompt {
     let (view, doc) = current!(cx.editor);
@@ -38,7 +39,7 @@ pub fn regex_prompt(
     Prompt::new(
         prompt,
         history_register,
-        |_input: &str| Vec::new(), // this is fine because Vec::new() doesn't allocate
+        completion_fn,
         move |cx: &mut crate::compositor::Context, input: &str, event: PromptEvent| {
             match event {
                 PromptEvent::Abort => {