-- $Id: goto.lua,v 1.13 2016/11/07 13:11:28 roberto Exp $
-- See Copyright Notice in file all.lua
collectgarbage()
local function errmsg (code, m)
local st, msg = load(code)
assert(not st and string.find(msg, m))
end
-- cannot see label inside block
errmsg([[ goto l1; do ::l1:: end ]], "label 'l1'")
errmsg([[ do ::l1:: end goto l1; ]], "label 'l1'")
-- repeated label
errmsg([[ ::l1:: ::l1:: ]], "label 'l1'")
-- undefined label
errmsg([[ goto l1; local aa ::l1:: ::l2:: print(3) ]], "local 'aa'")
-- jumping over variable definition
errmsg([[
do local bb, cc; goto l1; end
local aa
::l1:: print(3)
]], "local 'aa'")
-- jumping into a block
errmsg([[ do ::l1:: end goto l1 ]], "label 'l1'")
errmsg([[ goto l1 do ::l1:: end ]], "label 'l1'")
-- cannot continue a repeat-until with variables
errmsg([[
repeat
if x then goto cont end
local xuxu = 10
::cont::
until xuxu < x
]], "local 'xuxu'")
-- simple gotos
local x
do
local y = 12
goto l1
::l2:: x = x + 1; goto l3
::l1:: x = y; goto l2
end
::l3:: ::l3_1:: assert(x == 13)
-- long labels
do
local prog = [[
do
local a = 1
goto l%sa; a = a + 1
::l%sa:: a = a + 10
goto l%sb; a = a + 2
::l%sb:: a = a + 20
return a
end
]]
local label = string.rep("0123456789", 40)
prog = string.format(prog, label, label, label, label)
assert(assert(load(prog))() == 31)
end
-- goto to correct label when nested
do goto l3; ::l3:: end -- does not loop jumping to previous label 'l3'
-- ok to jump over local dec. to end of block
do
goto l1
local a = 23
x = a
::l1::;
end
while true do
goto l4
goto l1 -- ok to jump over local dec. to end of block
goto l1 -- multiple uses of same label
local x = 45
::l1:: ;;;
end
::l4:: assert(x == 13)
if print then
goto l1 -- ok to jump over local dec. to end of block
error("should not be here")
goto l2 -- ok to jump over local dec. to end of block
local x
::l1:: ; ::l2:: ;;
else end
-- to repeat a label in a different function is OK
local function foo ()
local a = {}
goto l3
::l1:: a[#a + 1] = 1; goto l2;
::l2:: a[#a + 1] = 2; goto l5;
::l3::
::l3a:: a[#a + 1] = 3; goto l1;
::l4:: a[#a + 1] = 4; goto l6;
::l5:: a[#a + 1] = 5; goto l4;
::l6:: assert(a[1] == 3 and a[2] == 1 and a[3] == 2 and
a[4] == 5 and a[5] == 4)
if not a[6] then a[6] = true; goto l3a end -- do it twice
end
::l6:: foo()
do -- bug in 5.2 -> 5.3.2
local x
::L1::
local y -- cannot join this SETNIL with previous one
assert(y == nil)
y = true
if x == nil then
x = 1
goto L1
else
x = x + 1
end
assert(x == 2 and y == true)
end
--------------------------------------------------------------------------------
-- testing closing of upvalues
local debug = require 'debug'
local function foo ()
local t = {}
do
local i = 1
local a, b, c, d
t[1] = function () return a, b, c, d end
::l1::
local b
do
local c
t[#t + 1] = function () return a, b, c, d end -- t[2], t[4], t[6]
if i > 2 then goto l2 end
do
local d
t[#t + 1] = function () return a, b, c, d end -- t[3], t[5]
i = i + 1
local a
goto l1
end
end
end
::l2:: return t
end
local a = foo()
assert(#a == 6)
-- all functions share same 'a'
for i = 2, 6 do
assert(debug.upvalueid(a[1], 1) == debug.upvalueid(a[i], 1))
end
-- 'b' and 'c' are shared among some of them
for i = 2, 6 do
-- only a[1] uses external 'b'/'b'
assert(debug.upvalueid(a[1], 2) ~= debug.upvalueid(a[i], 2))
assert(debug.upvalueid(a[1], 3) ~= debug.upvalueid(a[i], 3))
end
for i = 3, 5, 2 do
-- inner functions share 'b'/'c' with previous ones
assert(debug.upvalueid(a[i], 2) == debug.upvalueid(a[i - 1], 2))
assert(debug.upvalueid(a[i], 3) == debug.upvalueid(a[i - 1], 3))
-- but not with next ones
assert(debug.upvalueid(a[i], 2) ~= debug.upvalueid(a[i + 1], 2))
assert(debug.upvalueid(a[i], 3) ~= debug.upvalueid(a[i + 1], 3))
end
-- only external 'd' is shared
for i = 2, 6, 2 do
assert(debug.upvalueid(a[1], 4) == debug.upvalueid(a[i], 4))
end
-- internal 'd's are all different
for i = 3, 5, 2 do
for j = 1, 6 do
assert((debug.upvalueid(a[i], 4) == debug.upvalueid(a[j], 4))
== (i == j))
end
end
--------------------------------------------------------------------------------
-- testing if x goto optimizations
local function testG (a)
if a == 1 then
goto l1
error("should never be here!")
elseif a == 2 then goto l2
elseif a == 3 then goto l3
elseif a == 4 then
goto l1 -- go to inside the block
error("should never be here!")
::l1:: a = a + 1 -- must go to 'if' end
else
goto l4
::l4a:: a = a * 2; goto l4b
error("should never be here!")
::l4:: goto l4a
error("should never be here!")
::l4b::
end
do return a end
::l2:: do return "2" end
::l3:: do return "3" end
::l1:: return "1"
end
assert(testG(1) == "1")
assert(testG(2) == "2")
assert(testG(3) == "3")
assert(testG(4) == 5)
assert(testG(5) == 10)
--------------------------------------------------------------------------------
print'OK'
