Re: Non-linear lexical scoping (again) and an idea about __unset

["Soni \"They/Them\" L." <fakedme@...>]

On 2019-06-29 4:18 p.m., Philippe Verdy wrote:
> Le sam. 29 juin 2019 à 21:11, Soni "They/Them" L. <fakedme@gmail.com 
> <mailto:fakedme@gmail.com>> a écrit :
> >
> > There's nothing unsafe about "unset" because it's exactly equivalent to
> > renaming your (local) variables.
>
>
> If you unset a variable to get the effect of hiding it completely and 
> get access to the homonymous variable from an outer scope, and then 
> modifying it, it is unsafe.
>
> This does not happen when you redeclare a local variable that makes 
> the previous one out of scope and unreachable. As well when you set 
> that variable to nil this does not alow the homonymous variable from a 
> previous scope to become accessible.
>
> Really, "unset" is not needed and dangerous. Just use "local" instead.

"unset" is equivalent to "end". it just happens to, itself, be lexically 
scoped.

if each block (scope) could have a name and you could overlap them 
however you like:

do 'foo'
  local x = 1
  if a then 'bar'
    end 'foo'
    local z = 2
    x = z
    do 'foo'
  end 'bar'
  assert(x==1)
end 'foo'

"unset" is no more dangerous than using different names.