Merge lines if you press delete at beginning of a line

internal/editor/document/document.go

@@ -87,6 +87,11 @@ func (d *Document) AppendRow(s string) {
 	d.dirty = true
 }
 
+func (d *Document) MergeRows(to int, from int) {
+	d.rows[to].appendString(d.rows[from].toString())
+	d.delRow(from)
+}
+
 func (d *Document) ToString() string {
 	buf := gilo.NewBuffer()
 
@@ -117,3 +122,18 @@ func (d *Document) DelChar(at *gilo.Point) {
 func (d *Document) IsDirty() bool {
 	return d.dirty
 }
+
+func (d *Document) delRow(at int) {
+	var newSlice []*Row
+
+	// Split the array of rows at the specified index
+	start := d.rows[0:at]
+	end := d.rows[at+1 : d.RowCount()] // Skip the index in question
+
+	// Splice it back together
+	newSlice = append(newSlice, start...)
+	newSlice = append(newSlice, end...)
+
+	d.rows = newSlice
+	d.dirty = true
+}

internal/editor/document/row.go

@@ -59,6 +59,14 @@ func (r *Row) insertRune(ch rune, at int) {
 	r.update()
 }
 
+func (r *Row) appendString(str string) {
+	for _, ch := range str {
+		r.chars = append(r.chars, ch)
+	}
+
+	r.update()
+}
+
 func (r *Row) deleteRune(at int) {
 	if at < 0 || at >= r.Size() {
 		return

internal/editor/editor.go

@@ -94,11 +94,23 @@ func (e *editor) delChar() {
 		return
 	}
 
+	if e.cursor.X == 0 && e.cursor.Y == 0 {
+		return
+	}
+
 	if e.cursor.X > 0 {
 		at := e.cursor
 		at.X -= 1
 		e.document.DelChar(at)
 
 		e.cursor.X -= 1
+	} else {
+		// Move cursor to the current end of the previous line
+		e.cursor.X = e.document.Row(e.cursor.Y - 1).Size()
+
+		// Move the contents of the current row to the previous
+		e.document.MergeRows(e.cursor.Y - 1, e.cursor.Y)
+
+		e.cursor.Y -= 1
 	}
 }