The edge of "false 'empty' values" is absent in Lua, indeed, but the `a = b or c`, more often used in the form `b = b or c`, has, in Lua, still the problem that

The edge of "false 'empty' values" is absent in Lua, indeed, but the `a = b or c`, more often used in the form `b = b or c`, has, in Lua, still the problem that it will evaluate to `c` if `b` is `nil` and when b is `false` which may or may not be what one wants—and often one wants it not. The idiom is commonly used to assign a proper value to a variable that has not been set to an explicit value, i.e. a variable that is `nil`. The assignment `b = b or true` will set `b` to `true` if it was `nil` or `false`; assuming allowable values for `b` are `true` and `false` and the default is `true`, `b` will then never keep the value of `false` and always be set to `true`.