Python 3 to lua translator
Python version: 3.5
Lua version: 5.2
I want to know more about FEATURES!
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:
(venv) ******@****:~/Projects/python/python-lua$ python3 __main__.py tests/del.py
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
Insert lua code in the python
You can start your string with the tag [[luacode]] to simply insert lua code in the python. For example,
Python code:
def get_summ(a, b):
return a + b
print(get_summ(3, 5))
"""[[luacode]]
local c = 45
print(c)
"""
Lua code:
local function get_summ(a, b)
return (a + b)
end
print(get_summ(3, 5))
local c = 45
print(c)
Simple math:
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((math.pow(11, 2)))
print((math.floor(11 / 2)))
print((11 / 2))
print((((math.pow((5 + 34), 2)) / 53) * (24 - (6 * 3))))
Bitwise operations
Python code:
a = 0xFA23423
b = 0xAC23BD2
c = 0x548034D
print(a & b)
print((a & b) | c)
print(~((a & b) | c))
Lua code:
local a = 262288419
local b = 180501458
local c = 88605517
print((bit32.band(a, b)))
print((bit32.bor((bit32.band(a, b)), c)))
print(bit32.bnot((bit32.bor((bit32.band(a, b)), c))))
Function definitions with variable arguments number and default arguments
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)
print(*args)
hello("John", 12, "antikiller")
hello("Josh", 45)
hello("Jane")
Lua code:
local 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))
print(unpack(args))
end
hello("John", 12, "antikiller")
hello("Josh", 45)
hello("Jane")
Function decorators
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:
local function strong(old_fun)
local function wrapper(...)
local args = list {...}
local s = (("<strong>" + old_fun(unpack(args))) + "</strong>")
return s
end
return wrapper
end
local function italic(old_fun)
local function wrapper(...)
local args = list {...}
local s = (("<em>" + old_fun(unpack(args))) + "</em>")
return s
end
return wrapper
end
local function hello(name)
return (("Hello, " + name) + "!")
end
hello = strong(hello)
hello = italic(hello)
print(hello("John"))
If/elif/else, for and while loops
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.")
i = 10
while i > 0:
print(i)
i -= 1
Lua code:
local 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
local x = 100
if (50 < x and x < 150) then
print("50 < x < 150")
else
print("Something wrong.")
end
local i = 10
while (i > 0) do
print(i)
i = (i - 1)
end
If expression
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:
local function factorial(value)
return (value == 0) and 1 or (value * factorial((value - 1)))
end
print(factorial(5))
print(factorial(10))
print(factorial(3))
print(factorial(0))
Lists and dictionaries
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[2])
print(b[1][2])
print(c["firstname"], c["lastname"])
ch = c["children"][1]
print(ch["name"], ch["age"])
Lua code:
local a = list {1, 2, 5}
local b = list {list {1, 2, 3}, list {4, 5, 6}, list {7, 8, 9}}
local c = dict {["firstname"] = "John", ["lastname"] = "Doe", ["age"] = 42, ["children"] = list {dict {["name"] = "Sara", ["age"] = 4}}}
print(a[2])
print(b[1][2])
print(c["firstname"], c["lastname"])
local ch = c["children"][1]
print(ch["name"], ch["age"])
Python import statement
Python code:
import foo.bar
import bar as bar_ex
Lua code:
local bar = require "foo.bar"
local bar_ex = require "bar"
Lambda functions
Python code:
sqr = lambda x: x * x
print(sqr(2))
print(sqr(8))
Lua code:
local sqr = function(x) return (x * x) end
print(sqr(2))
print(sqr(8))
Python del operator
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:
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)
Python list and dictionary comprehensions
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)
b = {i: i ** 2 for i in range(5)}
for k, v in b.items():
print(k, v)
Lua code:
local 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)) then result.append((i * j)) end end end return result end)()
for item in a do
print(item)
::loop_label_1::
end
local b = (function() local result = dict {} for i in range(5) do result[i] = (math.pow(i, 2)) end return result end)()
for k, v in b.items() do
print(k, v)
::loop_label_2::
end
Classes
Python code:
class Animal:
PLANET = "Earth"
def __init__(self, name):
self.name = name
def say_hello(self):
print("Hello, my name is: " + self.name + "!")
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)
Lua code:
local 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
return Animal
end, {})
local 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, {Animal})
local sparky = Animal("Sparky")
local 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)
Loops continue statement
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_1
end
for j in range(10) do
if (j == 7) then
goto loop_label_2
end
print(i, " * ", j, " = ", (i * j))
::loop_label_2::
end
::loop_label_1::
end
Operators in and not in
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:
local a = list {1, 2, 3, 4}
local b = dict {["name"] = "John", ["age"] = 42}
local 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)))
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