add IO::Line::Multiple

binlib/io/line/multiple.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class IO::Line::Multiple
+  def initialize(lines, cursor)
+    @lines = lines
+    @cursor = cursor
+  end
+
+  def print(*strs, lineno:)
+    line = @lines[lineno]
+    if lineno > @cursor
+      line.io.cursor_down(lineno - @cursor)
+    elsif lineno < @cursor
+      line.io.cursor_up(lineno + @cursor)
+    end
+    @cursor = lineno
+    line.rewind.print(*strs)
+  end
+end