CODEWITHSUNDEEP
luaexecutablevala
gavr
gavr

Reputation: 945

Lua Returns the result of executing as string

I use luaVM in another programming language (Vala) and want to pass the code from vala to lua so that lua returns the result of executing this code as a string.

> s2="print (5+5)"
> s2
print (5+5)
> loadstring(s2)
function: 0x55834153f080
> func = loadstring(s2)
> func()
10

tried a lot of things, but I did not succeed, that is, I need instead of 10 was a variable of type string containing 10. So I could do vm.to_string(-1) of Vala and to obtain "10"

Upvotes: 4

Views: 1761

Answers (1)

Nifim
Nifim

Reputation: 5031

As Egor stated you can cast your result to a string before returning it using tostring.

I would also add you may want to use dostring not loadstring.

A load function in lua means to compile and not run the chunk, instead it returns a function when called will run the chunk.(loadfile, loadstring)

A do function will compile and run the contents.(dofile, dostring)

The details can be found here: Lua: 8 – Compilation, Execution, and Errors

Like dofile, loadfile also loads a Lua chunk from a file, but it does not run the chunk. Instead, it only compiles the chunk and returns the compiled chunk as a function.

This section speak more directly to loadfile but the page covers loadstring.

if dostring is not defined it can be like so:

function dostring(s)
    return assert(loadstring(s))()
end

If you are using a version of lua later then 5.1 loadstring becomes load

Upvotes: 4

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