How to use Lua in Vim?

Question

I'm using MacVim snapshot 134 (on Mac OS X 10.9.5), which has support for Lua:

$ vim --version | grep lua
+dialog_con_gui  +lua/dyn         +rightleft       +writebackup

I've got Lua installed and can even run it as an external command from within Vim:

:!lua
Lua 5.3.3  Copyright (C) 1994-2016 Lua.org, PUC-Rio
> print("hello")
hello
>

However,has("lua") returns 0:

:echo has("lua")
0

And attempting to use it through Vim's interface fails:

:lua print("hello")
E370: Could not load library liblua.5.2.dylib
Lua library cannot be loaded.

How can I get Vim to properly detect Lua? Is this a case of extremely strict required version matching, such that 5.2 means 5.2 period and 5.3.3 is not good enough?

I did notice this question over on SO, but that doesn't seem to help, as all the answers say to install a version of Vim with +lua/dyn, which I already have.

Answer 1

Yes, you Vim was compiled in such a way, that Vim will be looking for the dynamic library liblua5.2.dylib. If Vim cannot find that library, it obviously cannot use the lua extension.

This however is independent of usine :!lua which will shell out to the lua binary and run that command. For that, you do not need to compile Vim with +lua you just need to have a lua binary in your path, but that obviously cannot make use of the provided VimScript API.

If your system only provides a liblua5.3 library, you either have to compile Vim yourself with that library, or install additionally the liblua5.2 library in addition to the existing system wide library.

Answer 2

Christian Brabandt is correct, Vim requires the exact same version it was compiled for.

In my case, however, Vim still failed to load liblua.5.2.dylib even after installing Lua 5.2. I fixed that by adding a line to my .vimrc to explicitly tell Vim where to look:

set luadll=/path/to/liblua.5.2.dylib