Add previously missing docs where appropriate

1 files changed, 11 insertions, 0 deletions

diff --git a/src/tool/selection_tool.rs b/src/tool/selection_tool.rs
index 30f91bf..c790734 100644
--- a/src/tool/selection_tool.rs
+++ b/src/tool/selection_tool.rs
@@ -1,3 +1,11 @@
+//! Selection of items on the map.
+//!
+//! When selecting items on the map, the editor goes into a different mode than when editing a
+//! specific kind of item. Actions that are available for specific types of items become
+//! unavailable, while other actions that make use of the properties to a wide range of items
+//! become available instead.
+//! For this reason, the selection tool can be thought of as a kind of meta tool over tools.
+
 use super::Tool;
 use crate::colours::DEFAULT_COLOURS;
 use crate::map::Map;
@@ -5,11 +13,14 @@ use crate::math::{Rect, Surface, Vec2};
 use crate::transform::Transform;
 use raylib::core::drawing::{RaylibDraw, RaylibDrawHandle};
 
+/// The selection tool makes it possible to select any item on the map when activated.
 pub struct SelectionTool {
     selection_rect: Option<(Vec2<f64>, Vec2<f64>)>,
 }
 
 impl SelectionTool {
+    /// Create a new selection tool. There should be only one such tool per program instance and it
+    /// should be created in the editor.
     pub fn new() -> Self {
         Self {
             selection_rect: None,