trouble after install with luarocks

[SwissalpS]

installed using luarocks, downloaded example and tried to run it but get errors that SDL can't be found:

$ lua tutorial.lua
lua: tutorial.lua:6: module 'SDL' not found:
    no field package.preload['SDL']
    no file '/usr/share/lua/5.3/SDL.lua'
    no file '/usr/share/lua/5.3/SDL/init.lua'
    no file '/usr/lib64/lua/5.3/SDL.lua'
    no file '/usr/lib64/lua/5.3/SDL/init.lua'
    no file './SDL.lua'
    no file './SDL/init.lua'
    no file '/usr/lib64/lua/5.3/SDL.so'
    no file '/usr/lib64/lua/5.3/loadall.so'
    no file './SDL.so'
stack traceback:
    [C]: in function 'require'
    tutorial.lua:6: in main chunk
    [C]: in ?

$ lua -v
Lua 5.3.5  Copyright (C) 1994-2018 Lua.org, PUC-Rio

Which install step did I miss?

[ShortRoundDev]

Hi, @SwissalpS I'm not affiliated with this project but I had the same problem. You need to add your luarocks path to your LUA_PATH environment variable. When Lua looks for a required library file, it looks in all the directories listed by the LUA_PATH environment variable. I assume you are on either MacOS or Linux, based on your /usr/ paths. If you type

luarocks path

you will see an output for what your LUA_PATH should be. in a bash terminal, if you type

eval $(luarocks path)

it should set your LUA_PATH to the correct variable. If you want this to carry over to your next session, add that line to your ~/.bashrc file and it will set the path every time you open a terminal. I'm not sure if this solution will work on newer macbooks because they have moved from bash to zsh, and I have no experience with zsh. If you're using zsh and the problem continues, find someone who knows zsh and tell them the problem and they can probably help you

[SwissalpS]

Thank you very much @collinoswalt. That is a very good explanation.

I'm using Fedora 32 and no zsh Have made a wrapper shell script that first does

export LUA_CPATH="/usr/lib/lua/5.3/?.so;/usr/lib/lua/5.3/SDL/?.so;";

before running

lua mySDLapp.lua

eval $(luarocks path)

is better for most compatibility with other platforms. Thanks again :D