Re: Redefining locals

[Matt Hellige <matt@...>]

(Trying to get back to the topic...)

Again deferring to Scheme, redefinitions act the same as
assignments... So, for example:

    guile> (define x 3)
    guile> (define (f) x)
    guile> (f)
    3
    guile> (define x 5)
    guile> (f)
    5
    guile>

Here's R5RS again:

  At the top level of a program, a definition

  (define <variable> <expression>)

  has essentially the same effect as the assignment expression

  (set! <variable> <expression>)

  if <variable> is bound. If <variable> is not bound, however, then
  the definition will bind <variable> to a new location before
  performing the assignment, whereas it would be an error to perform a
  set! on an unbound variable.

I think it would be nice for lua to adopt a similar policy for locals,
as has been suggested by others. I'd like:

    local x = 3
    function f() print(x) end
    f()
    local x = 5
    f()

to print '3, 5' instead of '3, 3'... It seems like this still allows
the:

  local _, _ = f()

idiom to work as expected.


Matt

-- 
Matt Hellige                  matt@immute.net