Lua's ability to bind a closure to a mutable variable is a very powerful ability that I use all the time. But due to the way loop variables are handled, the exa

Lua's ability to bind a closure to a mutable variable is a very powerful ability that I use all the time. But due to the way loop variables are handled, the example that's "broken" in Python works "as expected" in Lua: fns = {} for i=1,10 do fns[i]= function() return i; end end for i=1,10 do print("fns[i]",fns[i]()) end This produces: fns[i] 1 fns[i] 2 fns[i] 3 fns[i] 4 fns[i] 5 fns[i] 6 fns[i] 7 fns[i] 8 fns[i] 9 fns[i] 10 If you change the set-up loop to look like this, though: local j for i=1,10 do j=i fns[i]= function() return i,j; end end ...then it prints: fns[i] 1 10 fns[i] 2 10 fns[i] 3 10 fns[i] 4 10 fns[i] 5 10 fns[i] 6 10 fns[i] 7 10 fns[i] 8 10 fns[i] 9 10 fns[i] 10 10 In that case, it has bound the mutable "j" to each of the 10 closures, though you can see it's created a new binding for i on each pass through the loop. It WILL create a new instance of the mutable "j" each time "local j" is executed, though, so if the above code is in a function or another block that's executed more than once, then each time those functions will be bound to a new "j". EDIT: Get the code markup right.