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, 1 insertions, 0 deletions

diff --git a/vis-core.h b/vis-core.h
index 22bec33..6554410 100644
--- a/vis-core.h
+++ b/vis-core.h
@@ -156,6 +156,7 @@ struct Vis {
 	sigjmp_buf sigbus_jmpbuf;            /* used to jump back to a known good state in the mainloop after (SIGBUS) */
 	Map *actions;                        /* registered editor actions / special keys commands */
 	lua_State *lua;                      /* lua context used for syntax highligthing */
+	VisEvent *event;
 };
 
 /** stuff used by multiple of the vis-* files */