    #!/usr/bin/env lua

    -- Metatables
    t = {
        __add=function(a,b)return a+b end,
        __sub=function(a,b)return a-b end,
        __mul=function(a,b)return a*b end,
        __div=function(a,b)return a/b end,
        __mod=function(a,b)return a%b end,
        __pow=function(a,b)return a^b end,
        __unm=function(a)return -a end,
        __idiv=function(a,b)return a//b end,
        __band=function(a,b)return a&b end,
        __bor=function(a,b)return a|b end,
        __bxor=function(a,b)return a~b end,
        __bnot=function(a)return ~a end,
        __shl=function(a,b)return a<<b end,
        __shr=function(a,b)return a>>b end,
        __concat=function(a,b)return a..b end,
        __len=function(a)return #a end,
        __eq=function(a,b)return a==b end,
        __lt=function(a,b)return a<b end,
        __le=function(a,b)return a<=b end,
        __index=function(t,k)return t[k] end,
        __newindex=function(t,k,v)return t[k]=v end,
        __call=function(f, ...)return f(...) end,

       __tostring=function(a)return tostring(a) end,
       __pairs=function(t)return pairs(a) end,
       -- setmetatable
       __metatable=true
       -- Garbage collector
       __gc=function() end
       -- Weak table
       __mode='k' -- or 'v'
    }

    a or b
    a and b
    a~=b
    a>=b
    true or false
    a or nil
    a::m
    a.m
    a;a

    -- String
    '\a'
    '\b'
    '\f'
    '\n'
    '\r'
    '\t'
    '\v'
    '\\'
    '\"'
    '\''
    '\z'
    '\xff'
    '\xFF'
    '\231'
    '\23'
    '\2'
    '\u{100201}' -- max 6 digits
    '\2a\ks' -- error

    'multi\
    line'
    'multi\z
    line'
    'multi\z    line\
    2'

    a = 'alo\n123"'
    a = "alo\n123\""
    a = '\97lo\10\04923"'
    a = [[alo
    123"]]
    a = [==[
    alo
    123"]==]

    -- Decimal
    3
    345
    0xff
    0xBEBADA

    -- Float
    3.
    .3
    3.0
    3.1416
    314.16e-2
    314.e+2
    0.31416E1
    34e1
    0.e3
    0x0.1E
    0xA23p-4
    0xA.p+4
    0x.ap4
    0X1.921FB54442D18P+1
    -- error
    32p
    0xp-4
    0x.p-4
    3.x

    -- single comment
    xyz()
    --[[
     long comment
    ]]
    xyz()

    a = { [f(1)] = g; "x", "y"; x = 1, f(x), [30] = 23; 45 }

    -- is equivalent to

    do
      local t = {}
      t[f(1)] = g
      t[1] = "x" -- 1st exp
      t[2] = "y" -- 2nd exp
      t.x = 1 -- t["x"] = 1
      t[3] = f(x) -- 3rd exp
      t[30] = 23
      t[4] = 45 -- 4th exp
      a = t
    end

    32-0x43+0x2-5
    return"a"
    return'a'
    return{}
    f(3)
    f'a'
    f"a"
    f{s=2}
    f[[s]]
    f[=[s]=]
    #a

    local CONSTANT = a

    a = {}
    local x = 20
    for i=1,10 do
      local y = 0
      a[i] = function () y=y+1; return x+y end
    end

    --! \brief gfind is deprecated
    string.gfind('s')
    string.gmatch('f')

    function foo()
      if x then
        function() end
        bar=function()
          if y then
            if z then end
          end
        end
      end
    end

    -- attributes
    local a<const> = 2
    local a<const> print(a)
    local f <close>, const <    const >
    local a <cloe>, b< cons >, c<const, d<close> ; a<b
    local a <cloe> -- bla,
    b< cons >
    local a <close> --[[
    b <const>]], b <const> --[[ xyz ]] , c <close>
    b< cons >

    --- \code
    --! a = 3
    --! \endcode
    a = 3