vis: refactor Lua integration

Lua support can now be disabled at compile time using:

 $ make CONFIG_LUA=0

This commit also adds an initial Lua API and provides a few
default hooks.

We now also require Lua >= 5.2 due to the uservalue constructs.
In principle the same functionality could be implemented using
function environments from Lua 5.1.

1 files changed, 2 insertions, 0 deletions

diff --git a/vis-cmds.c b/vis-cmds.c
index 477e29c..3a89d2a 100644
--- a/vis-cmds.c
+++ b/vis-cmds.c
@@ -595,6 +595,8 @@ static bool cmd_write(Vis *vis, Filerange *range, enum CmdOpt opt, const char *a
 		}
 		if (strcmp(file->name, *name) == 0)
 			file->stat = text_stat(text);
+		if (vis->event && vis->event->file_save)
+			vis->event->file_save(vis, file);
 	}
 	return true;
 }