locals.lua

-- $Id: locals.lua,v 1.37 2016/11/07 13:11:28 roberto Exp $
-- See Copyright Notice in file all.lua

print('testing local variables and environments')

local debug = require"debug"


-- bug in 5.1:

local function f(x) x = nil; return x end
assert(f(10) == nil)

local function f() local x; return x end
assert(f(10) == nil)

local function f(x) x = nil; local y; return x, y end
assert(f(10) == nil and select(2, f(20)) == nil)

do
  local i = 10
  do local i = 100; assert(i==100) end
  do local i = 1000; assert(i==1000) end
  assert(i == 10)
  if i ~= 10 then
    local i = 20
  else
    local i = 30
    assert(i == 30)
  end
end



f = nil

local f
x = 1

a = nil
load('local a = {}')()
assert(a == nil)

function f (a)
  local _1, _2, _3, _4, _5
  local _6, _7, _8, _9, _10
  local x = 3
  local b = a
  local c,d = a,b
  if (d == b) then
    local x = 'q'
    x = b
    assert(x == 2)
  else
    assert(nil)
  end
  assert(x == 3)
  local f = 10
end

local b=10
local a; repeat local b; a,b=1,2; assert(a+1==b); until a+b==3


assert(x == 1)

f(2)
assert(type(f) == 'function')


local function getenv (f)
  local a,b = debug.getupvalue(f, 1)
  assert(a == '_ENV')
  return b
end

-- test for global table of loaded chunks
assert(getenv(load"a=3") == _G)
local c = {}; local f = load("a = 3", nil, nil, c)
assert(getenv(f) == c)
assert(c.a == nil)
f()
assert(c.a == 3)

-- old test for limits for special instructions (now just a generic test)
_USPACE[=[
do
  local i = 2
  local p = 4    -- p == 2^i
  repeat
    for j=-3,3 do
      assert(load(string.format([[local a=%s;
                                        a=a+%s;
                                        assert(a ==2^%s)]], j, p-j, i), '')) ()
      assert(load(string.format([[local a=%s;
                                        a=a-%s;
                                        assert(a==-2^%s)]], -j, p-j, i), '')) ()
      assert(load(string.format([[local a,b=0,%s;
                                        a=b-%s;
                                        assert(a==-2^%s)]], -j, p-j, i), '')) ()
    end
    p = 2 * p;  i = i + 1
  until p <= 0
end
]=]

print'+'


if rawget(_G, "querytab") then
  -- testing clearing of dead elements from tables
  collectgarbage("stop")   -- stop GC
  local a = {[{}] = 4, [3] = 0, alo = 1, 
             a1234567890123456789012345678901234567890 = 10}

  local t = querytab(a)

  for k,_ in pairs(a) do a[k] = nil end
  collectgarbage()   -- restore GC and collect dead fiels in `a'
  for i=0,t-1 do
    local k = querytab(a, i)
    assert(k == nil or type(k) == 'number' or k == 'alo')
  end
end


-- testing lexical environments

assert(_ENV == _G)

do
local dummy
local _ENV = (function (...) return ... end)(_G, dummy)   -- {

do local _ENV = {assert=assert}; assert(true) end
mt = {_G = _G}
local foo,x
A = false    -- "declare" A
do local _ENV = mt
  function foo (x)
    A = x
    do local _ENV =  _G; A = 1000 end
    return function (x) return A .. x end
  end
end
assert(getenv(foo) == mt)
x = foo('hi'); assert(mt.A == 'hi' and A == 1000)
assert(x('*') == mt.A .. '*')

do local _ENV = {assert=assert, A=10};
  do local _ENV = {assert=assert, A=20};
    assert(A==20);x=A
  end
  assert(A==10 and x==20)
end
assert(x==20)


print('OK')

return 5,f

end   -- }