Re: Loading DSL Data

On 20 May 2014 14:31, Marc Lepage <mlepage@antimeta.com> wrote:

Hi, looking for some thoughts on loading DSL style data.

I have it working but would like to swap out the environment when doing so, so it doesn't trample on the global environment.

I have something like:

function load(name)

    local env = getfenv(0)

    setfenv(0, dsl)

    local data = "">

    setfenv(0, env)

end

Where I get the thread's environment, set the dsl table (with all the DSL functions) as the environment, load the data (using require), then restore the environment (presumably the _G table). Of course I should really pcall the load instead of require, and return the data, but that's the idea.

This is using Lua 5.1.5. I understand that Lua 5.2 changes the way environments are handled?

If anyone could offer tips here or even better, point to a page which explains a lot of this in this context, that would be super great.

Thanks,

Marc

Could you load the file with `loadfile` instead of `require` and then set the environment of the loaded chunk with `setfenv` before executing it? If you need to turn a module name into a full path, you can use an implementation of Lua 5.2's `package.searchpath` function like the one from Steve Donovan's Penlight compat module[1].

If/when you move to Lua 5.2, you can pass the environment table directly to `loadfile` instead of using `setfenv`.

Regards,

Choonster

[1] https://github.com/stevedonovan/Penlight/blob/master/lua/pl/compat.lua#L119-L135