lua - calling a function from a string - lua

Question

From what I've read on this site the below should work.
Can some kindly soul please point out where I'm going wrong?
I've embedded more description and print returns in the code hopefully to make easier reading
local m = {
{opt = "Solar Panels", cmd = "solarPanel"}
-- There are many more options here.
}
function doTheMenu()
print("Welcome to Spyder's Factory")
print("")
print("What would you like to make?")
local n = 1
local l = #m - 1
while true do --This while loop may or may not be relevant to the question, it's the menu
term.clear() --this is ComputerCraft lua, the term function is defined
term.setCursorPos(1,2) --elsewhere in an API
for i, j in pairs(m) do
if i == n then
if i < 10 then print(i, " ["..j.opt.."]") else print(i, " ["..j.opt.."]") end
fsel = j.cmd --set fsel to the function name I require in case of a break
tsel = j.opt --Ditto, tsel, human-friendly name
else
if i < 10 then print(i, " "..j.opt) else print(i, " "..j.opt) end
end
end
local a, b = os.pullEvent("key")
if b == 200 and n > 1 then n = n - 1 end
if b == 208 and n <= l then n = n + 1 end
if b == 28 then break end
end
write("\nSure, how many "..tsel.."? ")
qty = tonumber(read())
req[fsel] = req[fsel] + qty
str = fsel.."("..qty..")"
print("Loading function '"..fsel.."("..qty..")'") --Returns "Loading function 'solarPanel(1)'"
func = loadstring(str)
print(func) --Returns "function: 2cdfc5a7"
print("Loading function")
func() --The error line, Returns "string:1: attempt to call nil"
--tellUserWhatNeed()
--makeItHappen()
end
doTheMenu()
The issue is the code fails to run with the error:
string:1 attempt to call nil

Answer 1

Also what is term variable, if that's all your code, term is not defined and is null)
That said: either _G[fsel] is nil or fsel is nil ?
Are you sure you have function declared in _G with the name stored in fsel?
e.i. call before the problem line print (_G[fsel]) to see what it gives you.

Answer 2

This was the solution that ended up working:
local f = loadstring(str)
if f then
setfenv(f, getfenv())
f()
end
This replaces the lines above:
print("Loading function '"..fsel.."("..qty..")'")
func = loadstring(str)
print(func)
print("Loading function")
func()
As well as adding basic error handling for loading the function