Implement Selection::replace to replace a single range

Fixes #985

Co-authored-by: Daniel S Poulin <crimsonmage+github@gmail.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index 18af4d08..f3b5d2c8 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -362,6 +362,11 @@ impl Selection {
 
     /// Adds a new range to the selection and makes it the primary range.
     pub fn remove(mut self, index: usize) -> Self {
+        assert!(
+            self.ranges.len() > 1,
+            "can't remove the last range from a selection!"
+        );
+
         self.ranges.remove(index);
         if index < self.primary_index || self.primary_index == self.ranges.len() {
             self.primary_index -= 1;
@@ -369,6 +374,12 @@ impl Selection {
         self
     }
 
+    /// Replace a range in the selection with a new range.
+    pub fn replace(mut self, index: usize, range: Range) -> Self {
+        self.ranges[index] = range;
+        self.normalize()
+    }
+
     /// Map selections over a set of changes. Useful for adjusting the selection position after
     /// applying changes to a document.
     pub fn map(self, changes: &ChangeSet) -> Self {