enviornment of child function created by loadstring lua

Question

Why does the calls to f() and g() give different results? They both inherit environment from the parent function, run, but f() does not change j.

myString = "print('i,j in myString before setting', i, j);\
            i = 'fi'; j ='fj'\
            print('i,j in myString after setting', i,j)"
j = 1
print('j initial value', j)

function run(i)
    i = 'i'
    print('i initial value', i)
    f = loadstring(myString)
    if not f then
        print('load failed')
    else
        print('=== load ok, now execute')
        f()
        print('=== end of execution')
    end
    print('i,j after f()', i,j)

    g = function()
        i = 'gi'; j = 'gj'
    end
    g()
    print('i,j after g()', i,j)
end

run(i)

Results:

j initial value   1
i initial value   i
=== load ok, now execute
i,j in myString before setting   nil   1
i,j in myString after setting fi fj
=== end of execution
i,j after f()  i  fj
i,j after g()  gi gj

Note the different values of i after f() and g() calls.

Answer 1

You are referring to two separate i variables.

When you call f() it's accessing a global i, whereas you are accessing run's argument i in g().