Add `remove_selections` command (#1065)

* Add `remove_selections` command

* Document `remove_selections`

* Update helix-term/src/keymap.rs

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

4 files changed, 20 insertions, 7 deletions

diff --git a/book/src/keymap.md b/book/src/keymap.md
index 901c8471..7a9a4378 100644
--- a/book/src/keymap.md
+++ b/book/src/keymap.md
@@ -101,6 +101,7 @@
 |          | Expand selection to parent syntax node TODO: pick a key           | `expand_selection`                   |
 | `J`      | Join lines inside selection                                       | `join_selections`                    |
 | `K`      | Keep selections matching the regex                                | `keep_selections`                    |
+| `Alt-K`  | Remove selections matching the regex                              | `remove_selections`                  |
 | `$`      | Pipe each selection into shell command, keep selections where command returned 0 | `shell_keep_pipe`     |
 | `Ctrl-c` | Comment/uncomment the selections                                  | `toggle_comments`                    |
 
diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index f3b5d2c8..f7c7dbcb 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -528,14 +528,15 @@ impl<'a> IntoIterator for &'a Selection {
 
 // TODO: checkSelection -> check if valid for doc length && sorted
 
-pub fn keep_matches(
+pub fn keep_or_remove_matches(
     text: RopeSlice,
     selection: &Selection,
     regex: &crate::regex::Regex,
+    remove: bool,
 ) -> Option<Selection> {
     let result: SmallVec<_> = selection
         .iter()
-        .filter(|range| regex.is_match(&range.fragment(text)))
+        .filter(|range| regex.is_match(&range.fragment(text)) ^ remove)
         .copied()
         .collect();
 
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 738621b0..4352ee66 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -302,6 +302,7 @@ impl Command {
         format_selections, "Format selection",
         join_selections, "Join lines inside selection",
         keep_selections, "Keep selections matching regex",
+        remove_selections, "Remove selections matching regex",
         keep_primary_selection, "Keep primary selection",
         remove_primary_selection, "Remove primary selection",
         completion, "Invoke completion popup",
@@ -4320,12 +4321,12 @@ fn join_selections(cx: &mut Context) {
     doc.append_changes_to_history(view.id);
 }
 
-fn keep_selections(cx: &mut Context) {
-    // keep selections matching regex
+fn keep_or_remove_selections_impl(cx: &mut Context, remove: bool) {
+    // keep or remove selections matching regex
     let reg = cx.register.unwrap_or('/');
     let prompt = ui::regex_prompt(
         cx,
-        "keep:".into(),
+        if !remove { "keep:" } else { "remove:" }.into(),
         Some(reg),
         |_input: &str| Vec::new(),
         move |view, doc, regex, event| {
@@ -4334,7 +4335,9 @@ fn keep_selections(cx: &mut Context) {
             }
             let text = doc.text().slice(..);
 
-            if let Some(selection) = selection::keep_matches(text, doc.selection(view.id), &regex) {
+            if let Some(selection) =
+                selection::keep_or_remove_matches(text, doc.selection(view.id), &regex, remove)
+            {
                 doc.set_selection(view.id, selection);
             }
         },
@@ -4343,6 +4346,14 @@ fn keep_selections(cx: &mut Context) {
     cx.push_layer(Box::new(prompt));
 }
 
+fn keep_selections(cx: &mut Context) {
+    keep_or_remove_selections_impl(cx, false)
+}
+
+fn remove_selections(cx: &mut Context) {
+    keep_or_remove_selections_impl(cx, true)
+}
+
 fn keep_primary_selection(cx: &mut Context) {
     let (view, doc) = current!(cx.editor);
     // TODO: handle count
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index b2b865e4..f79978fb 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -577,7 +577,7 @@ impl Default for Keymaps {
             "=" => format_selections,
             "J" => join_selections,
             "K" => keep_selections,
-            // TODO: and another method for inverse
+            "A-K" => remove_selections,
 
             "," => keep_primary_selection,
             "A-," => remove_primary_selection,