From 0586770e35eb131955df10378bd97aed4b992937 Mon Sep 17 00:00:00 2001
From: ath3 <ha05190@protonmail.com>
Date: Sat, 13 Nov 2021 04:29:20 +0100
Subject: [PATCH] Add trim_selections command

---
 book/src/keymap.md         |  1 +
 helix-term/src/commands.rs | 29 +++++++++++++++++++++++++++++
 helix-term/src/keymap.rs   |  2 +-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/book/src/keymap.md b/book/src/keymap.md
index c544a472ebbbe..565be580749dd 100644
--- a/book/src/keymap.md
+++ b/book/src/keymap.md
@@ -88,6 +88,7 @@
 | `s`      | Select all regex matches inside selections                        | `select_regex`                       |
 | `S`      | Split selection into subselections on regex matches               | `split_selection`                    |
 | `Alt-s`  | Split selection on newlines                                       | `split_selection_on_newline`         |
+| `_`      | Trim whitespace from selections                                   | `trim_selections`                    |
 | `;`      | Collapse selection onto a single cursor                           | `collapse_selection`                 |
 | `Alt-;`  | Flip selection cursor and anchor                                  | `flip_selections`                    |
 | `,`      | Keep only the primary selection                                   | `keep_primary_selection`             |
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 48fd0ee01690f..2bd4c2ff282ef 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -272,6 +272,7 @@ impl Command {
         // TODO: different description ?
         goto_line_end_newline, "Goto line end",
         goto_first_nonwhitespace, "Goto first non-blank in line",
+        trim_selections, "Trim whitespace from selections",
         extend_to_line_start, "Extend to line start",
         extend_to_line_end, "Extend to line end",
         extend_to_line_end_newline, "Extend to line end",
@@ -584,6 +585,34 @@ fn goto_first_nonwhitespace(cx: &mut Context) {
     doc.set_selection(view.id, selection);
 }
 
+fn trim_selections(cx: &mut Context) {
+    let (view, doc) = current!(cx.editor);
+    let text = doc.text().slice(..);
+
+    static END_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"\S\s+$").unwrap());
+
+    let selection = doc.selection(view.id).clone().transform(|range| {
+        let mut start = range.from();
+        let mut end = range.to();
+        let start_byte = text.char_to_byte(start);
+
+        start += text
+            .chars_at(start)
+            .position(|x| !x.is_whitespace())
+            .unwrap_or(0);
+
+        if let Some(pos) = END_REGEX.find(&range.fragment(text)) {
+            end = text.byte_to_char(start_byte + pos.start()) + 1;
+        }
+        if range.anchor < range.head {
+            Range::new(start, end)
+        } else {
+            Range::new(end, start)
+        }
+    });
+    doc.set_selection(view.id, selection);
+}
+
 fn goto_window(cx: &mut Context, align: Align) {
     let (view, doc) = current!(cx.editor);
 
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index e3e0199571449..a95e8ecc3fd30 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -602,7 +602,7 @@ impl Default for Keymaps {
             // "Q" => replay_macro,
 
             // & align selections
-            // _ trim selections
+            "_" => trim_selections,
 
             "(" => rotate_selections_backward,
             ")" => rotate_selections_forward,