Updated todo file.

todo.md

@@ -3,4 +3,34 @@
 - Line number display
 - File opening by entering path
 - UI that wraps editors, for split view.
-- Redo functionality
+- Redo functionality
+
+
+- Clean up text buffer interface:
+    - Buffer should know its own tab size, font, etc.  Led will NOT support
+      multiple views into the same buffer with different fonts, tab sizes, etc.
+      This may seem an odd choice, but it helps to think of the text buffer as
+      a 2d representation of the text, for which it needs that information to
+      know the relative positions of things.
+    - Editing (these are undoable):
+        - insert_text
+        - remove_text
+        - move_text
+    - Undo functionality:
+        - Undo
+        - Redo
+        - Op section begin (for delimiting composite edit operations)
+        - Op section end
+    - Info:
+        - byte_count (useful when saving the file)
+        - grapheme_count
+        - line_count
+    - Position conversions:
+        - index -> line_col
+        - line_col -> index
+        - index -> vis_2d
+        - vis_2d -> index
+    - Reading text:
+        - grapheme at index (includes visual width in return)
+        - Bidirectional grapheme iterator (useful for search code, etc.)
+        - Bidirectional ine iterator (useful for display code)