Implement expand tab functionality, make tabwidth configurable

If expandtab is enabled then inserted tabs are replaced by tabwidth
amount of spaces.

Both settings apply to all windows files and can be changed via:

 :set tabwidth n                          # where 1 <= n <= 8
 :set expandtab (1|yes|true)|(0|no|false)

1 files changed, 6 insertions, 1 deletions

diff --git a/window.c b/window.c
index db35c4d..a3b28b6 100644
--- a/window.c
+++ b/window.c
@@ -91,6 +91,11 @@ static void window_cursor_set(Win *win, Line *line, int col);
 static bool window_viewport_up(Win *win, int n);
 static bool window_viewport_down(Win *win, int n);
 
+void window_tabwidth_set(Win *win, int tabwidth) {
+	win->tabwidth = tabwidth;
+	window_draw(win);
+}
+
 void window_selection_clear(Win *win) {
 	win->sel = text_range_empty();
 	window_draw(win);
@@ -489,7 +494,7 @@ Win *window_new(Text *text) {
 	}
 
 	win->text = text;
-	win->tabwidth = 8; // TODO make configurable
+	win->tabwidth = 8;
 
 	int width, height;
 	getmaxyx(win->win, height, width);