Python 3 to lua translator

Python version: 3.7 Lua version: 5.3

I want to know more about FEATURES!

Changes

• The latest version includes the use of 'operator overloading', and 'properties' in classes
• Type comparisons have been added
• Try/except blocks have been added
• String functions have been added (find, split, join, replace, basic slices (no step yet) rudimentary format (no typing, e.g. {.2f})
• The string functions required a large change to the overall code to include luas : operator. Classes etc have been changed substantially under the hood, but the user should not be able to notice the change.

Unsupported features

• Assigning static methods to variables and calling them is not permitted, only call static methods directly
• Assigning nested classes to variables and initializing them is not permitted, only initialize nested classes from within the main class directly.

Usage

As a standalone application

usage: python-lua [-h] [--show-ast] [--only-lua-init] [--no-lua-init] [IF]

Python to lua translator.

positional arguments:
  IF               A python script filename to translate it.

optional arguments:
  -h, --help       show this help message and exit
  --show-ast       Print python ast tree before code.
  --only-lua-init  Print only lua initialization code.
  --no-lua-init    Print lua code without lua init code.

For example: python3 __main__py tests/iterlist.py

As a packet

from pythonlua.translator import Translator

...

translator = Translator()
lua_code = translator.translate(python_code)

For example see runtests.py.

Warning

This translator defines some python functions in lua (len, range, enumerate, list, dict and other). For list and dict it also defines most methods like append() for list and items() for dict. You can find this definitions in the file pythonlua/luainit.lua. Also this definitions will be in the output, when you run translator as a standalone application.

For example

local string_meta = getmetatable("")
string_meta.__add = function(v1, v2)
    if type(v1) == "string" and type(v2) == "string" then
        return v1 .. v2
    end
    return v1 + v2
end

local str = tostring
local int = tonumber

local function len(t)
    return #t
end

local function range(from, to, step)
    assert(from ~= nil)
    
    if to == nil then
        to = from
        from = 1        
    end
    
    if step == nil then
        step = to > from and 1 or -1
    end

    local i = from
    
    return function()
        ret = i
        if (step > 0 and i > to) or (step < 0 and i < to) then
            return nil
        end
        
        i = i + step
        return ret
    end
end

local function list(t)
    local methods = {}

    methods.append = function(value)
        table.insert(t, value)
    end

    local iterator_index = nil

    setmetatable(t, {
        __index = function(self, index)
            if type(index) == "number" and index < 0 then
                return rawget(t, #t + index + 1)
            end

            return methods[index]
        end,
        __call = function(self, _, idx)
            if idx == nil and iterator_index ~= nil then
                iterator_index = nil
            end

            local v = nil
            iterator_index, v = next(t, iterator_index)

            return v
        end,
    })
    return t
end

function dict(t)
    local methods = {}
    
    methods.items = function()
         return pairs(t)
    end

    local key_index = nil
    
    setmetatable(t, {
        __index = methods,
        __call = function(self, _, idx)
            if idx == nil and key_index ~= nil then
                key_index = nil
            end

            key_index, _ = next(t, key_index)

            return key_index
        end,
    })
    
    return t
end

function enumerate(t, start)
    start = start or 1

    local i, v = next(t, nil)
    return function()
        local index, value = i, v
        i, v = next(t, i)

        if index == nil then
            return nil
        end

        return index + start - 1, value
    end
end
local a, b, c = 1, 2, 3
print(a, b, c)
a, b = nil, nil
print(a, b, c)
c = nil
print(a, b, c)

Features

Attributes

Open

Python code:

foo.bar.baz.one.two.three("Hello, world!")

Lua code:

foo.bar.baz.one.two:three(("Hello, world!"))

Output:

Class

Open

Python code:

class Animal:
    PLANET = "Earth"

    def __init__(self, name):
        self.name = name

    def say_hello(self):
        print("Hello, my name is: " + self.name + "!")

    @staticmethod
    def statichello(msg):
        print(msg+" from staticmethod")


class Dog(Animal):
    def say_hello(self):
        print("Hello, my name is: " + self.name + "!")
        self.bark()

    def bark(self):
        print("Bark! Bark! Bark!")


sparky = Animal("Sparky")
barky = Dog("Barky")

sparky.say_hello()
barky.say_hello()

barky.bark()

print("Animal.PLANET = ", Animal.PLANET)
print("sparky.PLANET = ", sparky.PLANET)
print("barky.PLANET = ", barky.PLANET)

Animal.PLANET = "Mars"

print("Animal.PLANET = ", Animal.PLANET)
print("sparky.PLANET = ", sparky.PLANET)

Animal.statichello("Hello")
Dog.statichello("Hello")

Lua code:

Animal = class(function(Animal)
    Animal.PLANET = ("Earth")
    function Animal.__init__(self, name)
        self.name = name
    end
    function Animal.say_hello(self)
        print(((("Hello, my name is: ") + self.name) + ("!")))
    end
    Animal.statichello = staticmethod(function(msg)
        print((msg + (" from staticmethod")))
    end)
    return Animal
end, "Animal", {}, {}, {})
Dog = class(function(Dog)
    function Dog.say_hello(self)
        print(((("Hello, my name is: ") + self.name) + ("!")))
        self:bark()
    end
    function Dog.bark(self)
        print(("Bark! Bark! Bark!"))
    end
    return Dog
end, "Dog", {Animal}, {}, {})
sparky = Animal(("Sparky"))
barky = Dog(("Barky"))
sparky:say_hello()
barky:say_hello()
barky:bark()
print(("Animal.PLANET = "), Animal.PLANET)
print(("sparky.PLANET = "), sparky.PLANET)
print(("barky.PLANET = "), barky.PLANET)
Animal.PLANET = ("Mars")
print(("Animal.PLANET = "), Animal.PLANET)
print(("sparky.PLANET = "), sparky.PLANET)
Animal:statichello(("Hello"))
Dog:statichello(("Hello"))

Output:

Hello, my name is: Sparky! Hello, my name is: Barky! Bark! Bark! Bark! Bark! Bark! Bark! Animal.PLANET = Earth sparky.PLANET = Earth barky.PLANET = Earth Animal.PLANET = Mars sparky.PLANET = Mars Hello from staticmethod Hello from staticmethod

Class_Extended

Open

Python code:

class example:

    def __init__(self, v):
        self.value = v

    def __add__(self, other):
        return example(self.value+other.value)

    def __sub__(self, other):
        return example(self.value-other.value)

    def __mul__(self, other):
        return example(self.value*other.value)

    def __truediv__(self, other):
        return example(self.value/other.value)

    def __lt__(self, other):
        return self.value < other.value

    def __str__(self):
        return str(self.value)


    def __contains__(self, item):
        if isinstance(item, str):
            return True
        return False

    @property
    def prop(self):
        return self.value

    @prop.setter
    def prop(self,new):
        if new > 5:
            self.value = new
class A:
    obj = None
    def __new__(cls, *args, **kwargs):
        if not cls.obj:
            cls.obj = object.__new__(cls)
        return cls.obj

    def __init__(self):
        print('init')


a = example(5)
b = example(6)
print(a+b)
print(a-b)
print(a*b)
print(a/b)
print(a.prop)
a.prop = 4
print(a.prop)
a.prop = 6
print(a.prop)

if "string" in a:
    print("yes")
if 1 in a:
    print("no")

a = A()
b = A()
print(a==b)

Lua code:

example = class(function(example)
    function example.__init__(self, v)
        self.value = v
    end
    function example.__add__(self, other)
        return example((self.value + other.value))
    end
    function example.__sub__(self, other)
        return example((self.value - other.value))
    end
    function example.__mul__(self, other)
        return example((self.value * other.value))
    end
    function example.__truediv__(self, other)
        return example((self.value / other.value))
    end
    function example.__lt__(self, other)
        return (self.value < other.value)
    end
    function example.__str__(self)
        return str(self.value)
    end
    function example.__contains__(self, item)
        if isinstance(item, str) then
            return true
        end
        return false
    end
    example.prop = property(function(self)
        return self.value
    end)
    example.prop = example.prop:setter(function(self, new)
        if (new > 5) then
            self.value = new
        end
    end)
    return example
end, "example", {}, {__add = "__add__", __sub = "__sub__", __mul = "__mul__", __div = "__truediv__", __lt = "__lt__", __tostring = "__str__", __in = "__contains__"}, {prop = "example.prop"})
A = class(function(A)
    A.obj = nil
    function A.__new__(cls, ...)
        local args = list {...}
        if not cls.obj then
            cls.obj = object:__new__(cls)
        end
        return cls.obj
    end
    function A.__init__(self)
        print(("init"))
    end
    return A
end, "A", {}, {}, {})
a = example(5)
b = example(6)
print((a + b))
print((a - b))
print((a * b))
print((a / b))
print(a.prop)
a.prop = 4
print(a.prop)
a.prop = 6
print(a.prop)
if (operator_in(("string"), a)) then
    print(("yes"))
end
if (operator_in(1, a)) then
    print(("no"))
end
a = A()
b = A()
print((a == b))

Output:

11 -1 30 0.83333333333333 5 5 6 yes init init true

Comments

Open

Python code:

"""Documentation comments test"""

class Animal:
    """Class-level docstring"""
    pass

def foo():
    """Function-level docstring"""
    pass

name = "John " + "Parrish"

print(name)
print("Hello!")

Lua code:

--[[ Documentation comments test ]]
Animal = class(function(Animal)
    --[[ Class-level docstring ]]
    return Animal
end, "Animal", {}, {}, {})
function foo()
    --[[ Function-level docstring ]]
end
name = (("John ") + ("Parrish"))
print(name)
print(("Hello!"))

Output:

John Parrish Hello!

Comprehensions

Open

Python code:

a = [i * j for i in range(5) for j in range(3) if i * j % 2 == 0 and i > 0 and j > 0]

for item in a:
    print(item)

lst = ["a","b","c","d","e"]
b = {lst[i]: i ** 2 for i in range(5)}

for k in lst:
    print(k,b[k])

Lua code:

a = (function() local result = list {} for i in range(5) do for j in range(3) do if (((math.fmod((i * j), 2)) == 0) and (i > 0) and (j > 0)) then result:append((i * j)) end end end return result end)()
for item in a do
    print(item)
    ::loop_label_1::
end
lst = list {("a"), ("b"), ("c"), ("d"), ("e")}
b = (function() local result = dict {} for i in range(5) do result[lst[i]] = (i ^ 2) end return result end)()
for k in lst do
    print(k, b[k])
    ::loop_label_2::
end

Output:

2 2 4 6 4 8 a 0.0 b 1.0 c 4.0 d 9.0 e 16.0

Continue

Open

Python code:

for i in range(10):
    if i == 5:
        continue
    for j in range(10):
        if j == 7:
            continue
        print(i, " * ", j, " = ", i * j)

Lua code:

for i in range(10) do
    if (i == 5) then
        goto loop_label_3
    end
    for j in range(10) do
        if (j == 7) then
            goto loop_label_4
        end
        print(i, (" * "), j, (" = "), (i * j))
        ::loop_label_4::
    end
    ::loop_label_3::
end

Output:

0 * 0 = 0 0 * 1 = 0 0 * 2 = 0 0 * 3 = 0 0 * 4 = 0 0 * 5 = 0 0 * 6 = 0 0 * 8 = 0 0 * 9 = 0 1 * 0 = 0 1 * 1 = 1 1 * 2 = 2 1 * 3 = 3 1 * 4 = 4 1 * 5 = 5 1 * 6 = 6 1 * 8 = 8 1 * 9 = 9 2 * 0 = 0 2 * 1 = 2 2 * 2 = 4 2 * 3 = 6 2 * 4 = 8 2 * 5 = 10 2 * 6 = 12 2 * 8 = 16 2 * 9 = 18 3 * 0 = 0 3 * 1 = 3 3 * 2 = 6 3 * 3 = 9 3 * 4 = 12 3 * 5 = 15 3 * 6 = 18 3 * 8 = 24 3 * 9 = 27 4 * 0 = 0 4 * 1 = 4 4 * 2 = 8 4 * 3 = 12 4 * 4 = 16 4 * 5 = 20 4 * 6 = 24 4 * 8 = 32 4 * 9 = 36 6 * 0 = 0 6 * 1 = 6 6 * 2 = 12 6 * 3 = 18 6 * 4 = 24 6 * 5 = 30 6 * 6 = 36 6 * 8 = 48 6 * 9 = 54 7 * 0 = 0 7 * 1 = 7 7 * 2 = 14 7 * 3 = 21 7 * 4 = 28 7 * 5 = 35 7 * 6 = 42 7 * 8 = 56 7 * 9 = 63 8 * 0 = 0 8 * 1 = 8 8 * 2 = 16 8 * 3 = 24 8 * 4 = 32 8 * 5 = 40 8 * 6 = 48 8 * 8 = 64 8 * 9 = 72 9 * 0 = 0 9 * 1 = 9 9 * 2 = 18 9 * 3 = 27 9 * 4 = 36 9 * 5 = 45 9 * 6 = 54 9 * 8 = 72 9 * 9 = 81

Decorator

Open

Python code:

def strong(old_fun):
    def wrapper(*args):
        s = "<strong>" + old_fun(*args) + "</strong>"
        return s
    return wrapper

def italic(old_fun):
    def wrapper(*args):
        s = "<em>" + old_fun(*args) + "</em>"
        return s
    return wrapper

@italic
@strong
def hello(name):
    return "Hello, " + name + "!"

print(hello("John"))

Lua code:

function strong(old_fun)
    local function wrapper(...)
        local args = list {...}
        local s = ((("<strong>") + old_fun(unpack(args))) + ("</strong>"))
        return s
    end
    return wrapper
end
function italic(old_fun)
    local function wrapper(...)
        local args = list {...}
        local s = ((("<em>") + old_fun(unpack(args))) + ("</em>"))
        return s
    end
    return wrapper
end
hello = italic(strong(function(name)
    return ((("Hello, ") + name) + ("!"))
end))
print(hello(("John")))

Output:

Hello, John!

Defaultargs

Open

Python code:

def hello(name, age=20, nickname="", *args):
    print("Hello, my name is " + name + " and I'm " + str(age))
    print("My nickname is " + nickname)

hello("John", 12, "antikiller")
hello("Josh", 45)
hello("Jane")

Lua code:

function hello(name, age, nickname, ...)
    age = age or 20
    nickname = nickname or ("")
    local args = list {...}
    print((((("Hello, my name is ") + name) + (" and I'm ")) + str(age)))
    print((("My nickname is ") + nickname))
end
hello(("John"), 12, ("antikiller"))
hello(("Josh"), 45)
hello(("Jane"))

Output:

Hello, my name is John and I'm 12 My nickname is antikiller Hello, my name is Josh and I'm 45 My nickname is Hello, my name is Jane and I'm 20 My nickname is

Del

Open

Python code:

a, b, c = 1, 2, 3
print(a, b, c)
del a, b
print(a, b, c)
del c
print(a, b, c)

Lua code:

a, b, c = 1, 2, 3
print(a, b, c)
a, b = nil, nil
print(a, b, c)
c = nil
print(a, b, c)

Output:

1 2 3 nil nil 3 nil nil nil

Factorial

Open

Python code:

def factorial(value):
    return 1 if value == 0 else value * factorial(value - 1)

print(factorial(5))
print(factorial(10))
print(factorial(3))
print(factorial(0))

Lua code:

function factorial(value)
    return (function() if (value == 0) then return 1 end return (value * factorial((value - 1))) end)()
end
print(factorial(5))
print(factorial(10))
print(factorial(3))
print(factorial(0))

Output:

120 3628800 6 1

For

Open

Python code:

for i in range(10):
    print(i)

k = [1, 2, 3]
print(len(k))

Lua code:

for i in range(10) do
    print(i)
    ::loop_label_5::
end
k = list {1, 2, 3}
print(len(k))

Output:

0 1 2 3 4 5 6 7 8 9 3

Global

Open

Python code:

foo = 42

def bar():
    global foo
    foo = 34

print("foo = ", foo)
bar()
print("foo = ", foo)

Lua code:

foo = 42
function bar()
    foo = 34
end
print(("foo = "), foo)
bar()
print(("foo = "), foo)

Output:

foo = 42 foo = 34

Ifelse

Open

Python code:

a = 45
b = 0

if a > 5 and b < 34:
    print("a > 5")
    if a >= 45:
        print("a >= 45")
    else:
        print("a < 45")
elif a < 5:
    print("a < 5")
else:
    print("a == 5")

if a == 45:
    print("a == 45")

x = 100
if 50 < x < 150:
    print("50 < x < 150")
else:
    print("Something wrong.")

Lua code:

a = 45
b = 0
if ((a > 5) and (b < 34)) then
    print(("a > 5"))
    if (a >= 45) then
        print(("a >= 45"))
    else
        print(("a < 45"))
    end
elseif (a < 5) then
    print(("a < 5"))
else
    print(("a == 5"))
end
if (a == 45) then
    print(("a == 45"))
end
x = 100
if (50 < x and x < 150) then
    print(("50 < x < 150"))
else
    print(("Something wrong."))
end

Output:

a > 5 a >= 45 a == 45 50 < x < 150

Import

Open

Python code:

import foo.bar
import bar as bar_ex

Lua code:

local bar = require("foo.bar")
local bar_ex = require("bar")

Output:

In

Open

Python code:

a = [1, 2, 3, 4]
b = {
    "name": "John",
    "age": 42,
}

c = "Hello, world!"

if 2 < 3:
    print("2 < 3")

print(1 in a)
print(2 in a)
print(5 in a)
print("name" in b)
print("surname" in b)
print("Hell" in c)
print("world" in c)
print("Foo" in c)
print("Hells" not in c)

Lua code:

a = list {1, 2, 3, 4}
b = dict {[("name")] = ("John"), [("age")] = 42}
c = ("Hello, world!")
if (2 < 3) then
    print(("2 < 3"))
end
print((operator_in(1, a)))
print((operator_in(2, a)))
print((operator_in(5, a)))
print((operator_in(("name"), b)))
print((operator_in(("surname"), b)))
print((operator_in(("Hell"), c)))
print((operator_in(("world"), c)))
print((operator_in(("Foo"), c)))
print((not operator_in(("Hells"), c)))

Output:

2 < 3 true true false true false true true false true

Isinstance

Open

Python code:

class A:
    pass
class B(A):
    pass
a=A()
b=B()
print(isinstance(a,A))
print(isinstance(a,B))
print(isinstance(b,A))
print(isinstance(b,B))

Lua code:

A = class(function(A)
    return A
end, "A", {}, {}, {})
B = class(function(B)
    return B
end, "B", {A}, {}, {})
a = A()
b = B()
print(isinstance(a, A))
print(isinstance(a, B))
print(isinstance(b, A))
print(isinstance(b, B))

Output:

true false true true

Iterdict

Open

Python code:

book = {
    "title": "Harry Potter and the philosopher's stone",
    "author": "J. K. Rowling",
    "year": 1997,
}

k = 0
for i in book:
    k += 1
    if k > 1:
        break

for i in book:
    pass

Lua code:

book = dict {[("title")] = ("Harry Potter and the philosopher's stone"), [("author")] = ("J. K. Rowling"), [("year")] = 1997}
k = 0
for i in book do
    k = (k + 1)
    if (k > 1) then
        break
    end
    ::loop_label_6::
end
for i in book do
    ::loop_label_7::
end

Output:

Iterlist

Open

Python code:

a = [1, 4, 8, 16, 52, 34, 78, 342]

k = 0

strange_sum = 0
for i in a:
    k += 1
    if k > 3:
        break

    print("Current i is: ", i)
    strange_sum += i

print("After break: ")

for i in a:
    print("Current i is: ", i)
    strange_sum += i

print("Some strange sum is: ", strange_sum)

Lua code:

a = list {1, 4, 8, 16, 52, 34, 78, 342}
k = 0
strange_sum = 0
for i in a do
    k = (k + 1)
    if (k > 3) then
        break
    end
    print(("Current i is: "), i)
    strange_sum = (strange_sum + i)
    ::loop_label_8::
end
print(("After break: "))
for i in a do
    print(("Current i is: "), i)
    strange_sum = (strange_sum + i)
    ::loop_label_9::
end
print(("Some strange sum is: "), strange_sum)

Output:

Current i is: 1 Current i is: 4 Current i is: 8 After break: Current i is: 1 Current i is: 4 Current i is: 8 Current i is: 16 Current i is: 52 Current i is: 34 Current i is: 78 Current i is: 342 Some strange sum is: 548

Lambda

Open

Python code:

sqr = lambda x: x * x
print(sqr(2))
print(sqr(8))

Lua code:

sqr = function(x) return (x * x) end
print(sqr(2))
print(sqr(8))

Output:

4 64

Listdict

Open

Python code:

a = [1, 2, 5]
b = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9],
]

c = {
    "firstname": "John",
    "lastname": "Doe",
    "age": 42,
    "children": [
        {
            "name": "Sara",
            "age": 4,
        },
    ],
}

print(a[1])
print(b[0][1])
print(c["firstname"], c["lastname"])

ch = c["children"][0]
print(ch["name"], ch["age"])

Lua code:

a = list {1, 2, 5}
b = list {list {1, 2, 3}, list {4, 5, 6}, list {7, 8, 9}}
c = dict {[("firstname")] = ("John"), [("lastname")] = ("Doe"), [("age")] = 42, [("children")] = list {dict {[("name")] = ("Sara"), [("age")] = 4}}}
print(a[1])
print(b[0][1])
print(c[("firstname")], c[("lastname")])
ch = c[("children")][0]
print(ch[("name")], ch[("age")])

Output:

2 2 John Doe Sara 4

Localvars

Open

Python code:

i = 10
j = 5
while i > 0:
    print(i)
    i = i - 1
    test = 3434

test = 56

def fact(n):
    return 1 if n == 0 else n * fact(n - 1)

class Foo:
    def __init__(self):
        self.cls_var = 45
        localvar = 56

Lua code:

i = 10
j = 5
while (i > 0) do
    print(i)
    i = (i - 1)
    local test = 3434
    ::loop_label_10::
end
test = 56
function fact(n)
    return (function() if (n == 0) then return 1 end return (n * fact((n - 1))) end)()
end
Foo = class(function(Foo)
    function Foo.__init__(self)
        self.cls_var = 45
        local localvar = 56
    end
    return Foo
end, "Foo", {}, {}, {})

Output:

10 9 8 7 6 5 4 3 2 1

Luacode

Open

Python code:

def get_summ(a, b):
    return a + b

print(get_summ(3, 5))

"""[[luacode]]
local c = 45
print(c)
"""


"""[[luacode=tests\\luacode.lua]]"""

Lua code:

function get_summ(a, b)
    return (a + b)
end
print(get_summ(3, 5))

local c = 45
print(c)

print('luacode imported')

Output:

8 45 luacode imported

Nestedclass

Open

Python code:

class Foo:
    class Bar:
        def __init__(self):
            print("__init__ from Bar")
    
    def __init__(self):
        print("__init__ from Foo")
        Foo.Bar()

Foo()
Foo.Bar()

Lua code:

Foo = class(function(Foo)
    Foo.Bar = class(function(Bar)
        function Bar.__init__(self)
            print(("__init__ from Bar"))
        end
        return Bar
    end, "Bar", {}, {}, {})
    function Foo.__init__(self)
        print(("__init__ from Foo"))
        Foo.Bar()
    end
    return Foo
end, "Foo", {}, {}, {})
Foo()
Foo:Bar()

Output:

init from Foo init from Bar init from Bar

Simple_Math

Open

Python code:

print(5 + 3)
print(18 - 2)
print(5 * 5)
print(64 / 2)
print(11 ** 2)
print(11 // 2)
print(11 / 2)
print(((5 + 34) ** 2 / 53) * (24 - 6 * 3))

Lua code:

print((5 + 3))
print((18 - 2))
print((5 * 5))
print((64 / 2))
print((11 ^ 2))
print((math.floor(11 / 2)))
print((11 / 2))
print(((((5 + 34) ^ 2) / 53) * (24 - (6 * 3))))

Output:

8 16 25 32.0 121.0 5 5.5 172.18867924528

Strings

Open

Python code:

print("test" + "ing")
print("test{}".format("ing2"))
str = "ab{}cb{}"
print(str.replace("b","d"))
print(str.find("c"))
print(str.format("asdf","asdf2"))
print(str[1:5])

print("()".join(str.split("{}")))

print("""a
multiline
string
""")

Lua code:

print((("test") + ("ing")))
print(("test{}"):format(("ing2")))
str = ("ab{}cb{}")
print(str:replace(("b"), ("d")))
print(str:find(("c")))
print(str:format(("asdf"), ("asdf2")))
print(str[slice(1,5,nil)])
print(("()"):join(str:split(("{}"))))
print(([[a
multiline
string
]]))

Output:

testing testing2 ad{}cd{} 4 abasdfcbasdf2 b{}c ab()cb() a multiline string

Try

Open

Python code:

try:
    print('test')
    xpcall()
    print('still going')
except:
    print('Error in function')
print('running')

Lua code:

xpcall(function()
    print(("test"))
    xpcall()
    print(("still going"))
end, function(Error)
    print(("Error in function"))
end)
print(("running"))

Output:

test Error in function running

Type

Open

Python code:

class A:
    pass
a = A()
if isinstance(a,A) and type(a) is A:
    print("class typing works")
b = 5.5
if isinstance(b,float):  # or int, since both convert to number in lua
    print("number typing works")
c = "my string"
if isinstance(c,str):
    print("string typing works")
d = []
if type(d) is list and isinstance(d,list):
    print("list type works")
e = {}
if type(e) is dict and isinstance(e,dict):
    print("dict type works")
if type(d) is dict or type(e) is list:
    print("not good")

Lua code:

A = class(function(A)
    return A
end, "A", {}, {}, {})
a = A()
if (isinstance(a, A) and (type(a) == A)) then
    print(("class typing works"))
end
b = 5.5
if isinstance(b, float) then
    print(("number typing works"))
end
c = ("my string")
if isinstance(c, str) then
    print(("string typing works"))
end
d = list {}
if ((type(d) == list) and isinstance(d, list)) then
    print(("list type works"))
end
e = dict {}
if ((type(e) == dict) and isinstance(e, dict)) then
    print(("dict type works"))
end
if ((type(d) == dict) or (type(e) == list)) then
    print(("not good"))
end

Output:

class typing works number typing works string typing works list type works dict type works

Unaryop

Open

Python code:

a = 45
a = -a

b = +a

c = ~a

test = True
nt = not test

print(a, b, c)
print(test, nt)

Lua code:

a = 45
a = -a
b = a
c = bit32.bnot(a)
test = true
nt = not test
print(a, b, c)
print(test, nt)

Output:

-45 -45 44 true false

Varargs

Open

Python code:

def foo():
    pass

def varargs(name, *args):
    print("Name is: ", name)
    print(*args)

varargs("first", 1, 3, 6, 4, 7)
varargs("second", "hello", "python", "world")

Lua code:

function foo()

end
function varargs(name, ...)
    local args = list {...}
    print(("Name is: "), name)
    print(unpack(args))
end
varargs(("first"), 1, 3, 6, 4, 7)
varargs(("second"), ("hello"), ("python"), ("world"))

Output:

Name is: first 1 3 6 4 7 Name is: second hello python world

Variables

Open

Python code:

a = 45
b = 100

a, b = b, a

c = a * b
d = c / (1 + 1)

print(a)
print(b)
print(c)
print(d)

Lua code:

a = 45
b = 100
a, b = b, a
c = (a * b)
d = (c / (1 + 1))
print(a)
print(b)
print(c)
print(d)

Output:

100 45 4500 2250.0

While

Open

Python code:

i = 10
while i > 0:
    print(i)
    i -= 1

Lua code:

i = 10
while (i > 0) do
    print(i)
    i = (i - 1)
    ::loop_label_11::
end

Output:

10 9 8 7 6 5 4 3 2 1

With

Open

Python code:

with open("output") as output_file:
    output_file.write(input_file.read())

Lua code:

do
    local output_file = open(("output"))
    output_file:write(input_file:read())
end

Output: