Typical OOP in Lua looks something like this:
local Class = {}
function Class:new( o )
o = o or {}
setmetatable( o, self )
self.__index = self
return o
end
return Classwith torch/class it looks something like this:
local A = class('A')
function A:__init(stuff)
self.stuff = stuff
end
function A:run()
print(self.stuff)
endwith luaclass it looks something like this:
local Test = Class {
var = 5,
__init__ = function(self, p1, p2, p3)
self.stuff = {p1, p2, p3}
end,
test = function(self)
print(self.var, self.stuff)
end
}
local c = Test(1,2,3)
c:test()I like the style of the last way :) (because of the table-based format). This style is possible because Lua allows for the removal of parentheses in function calls with a single table argument. Behind the scenes, the Class function is fairly simple (only 21 lines of code). All it does is create a metatable for the table argument with __call defined to initiate a class/its parent classes (with their own metatables if applicable).
with torch/class it looks something like this:
local B = class('B', 'A')
function B:__init(stuff)
A.__init(self, stuff) -- call the parent init
end
function B:run5()
for i=1,5 do
print(self.stuff)
end
endwith luaclass it looks something like this:
local Thing = Class {
name = '',
__init__ = function(self, name)
self.name = name
end,
__tostring = function(self)
return tostring(self.name)
end
}
local Person = Class({
talk = function(self)
print(string.format('Hello, my name is %s', self.name))
end
}, Thing)
local t = Thing('one')
local p = Person('A')
print(t)
print(p)
p:talk()
print(pcall(t.talk, t))require '../luaclass'
local List = Class {
__init__ = function(self)
self.l = {}
end,
append = function(self, value)
table.insert(self.l, value)
end,
__index = function(self, idx)
return self.l[idx]
end,
collect = function(self) return next, self.l end,
__tostring = function(self)
local rv = '['
local size = #self.l
for key, val in pairs(self.l) do
local delim
if key == size then delim = ''
else delim = ', ' end
rv = rv .. tostring(val) .. delim
end
rv = rv .. ']'
return rv
end,
__len = function(self) return #self.l end,
__call = function(self)
local i, v = next(self.l, self.idx)
self.idx = i
return v
end,
iter = Generator( -- coroutine
function(self)
for key, val in pairs(self.l) do
yield(val)
end
end
)
}
local l = List()
for i = 1, 5 do l:append(i) end
print(l)
print(l[1], l[2], l[100])
for val in l:collect() do
print(val)
end
for val in l do
print(val)
end
print(l()) --restarts at index 1
print(l())
while true do
local rv = l:iter()
if rv == nil then break
else print(rv) end
endThoughts, feedback, and contributions are all welcome.