luaclass

After thinking about OOP and Lua and trying to mod Factorio, I decided to make a library for easier OOP programming. It shares the most principles with this repository, which is also named luaclass, but I kind of think that my one is better :)

Examples

You may notice that this repository has a examples/ folder with two files: str.lua and list.lua. The first one has a wrapper class Str for Lua strings that has several features like multiplying by using *. The second example is more complicated - it has a List class with many features:

concatenation by using four methods (a .. b, a + b, a:plus(b), List.concat(a, b)),
multiplication,
working pairs and ipairs,
at function for getting an element by index - __index would interfere with the internal implementation,
tostring function creating a string like "[hello, world, !]".

Usage

Okay, examples are good, but not everyone likes to only read code... So here's some "documentation" for the library, and... MAGIC METHODS HAVE SYNONYMS! USE THE SYNONYMS!

class(class, parent?) -> table

This function creates a "class" using the data in class argument and (optionally) extends it from another class. Example:

local foo
foo = class {
	constructor = function (self) print('foo::constructor()') end
}
foo:new() -- prints "foo::constructor()"
local bar
bar = class({
	constructor = function (self) print('bar::constructor()') end
}, foo)
bar:new() -- prints "bar::constructor()" but doesn't call superclass constructor!

local baz
baz = class({
	constructor = function (self)
		self.super.constructor(self) -- <== this calls the superclass constructor!
		print('baz::constructor()')
	end
}, foo)
baz:new() -- prints both "foo::constructor()" and "baz::constructor()"

class:new(...) -> table

This function creates an instance of the class. Example:

foo = class {
	constructor = function (self)
		print('created a foo object')
	end
}

local fooobj = foo:new()

class:is(smth) -> boolean

This function checks is this value an instance of this class. Doesn't check for subclasses! Example:

foo = class {}
bar = class ({}, foo)
baz = class ({}, bar)
print(bar:is(foo:new())) -- prints "false" because a `foo` object isn't a `bar` object
print(foo:is(bar:new())) -- prints "false" because as I said, it doesn't check for subclasses
print(baz:is(baz:new())) -- prints "true" because a `baz` object is a `baz` object

object:constructor(...)

Just calls the constructor.

object.__class

This field is the class of this object.

"Magic" methods

Arithmetic

`plus`

A method to get the sum of the two objects.

`minus`

A method to subtract B from A.

`times`

A method to multiply A by B.

`divide`

A method to divide A by B.

`power`

A method to get the "B"-th power of "A".

`modulo`

A method to modulo this object by another one.

`idivide`

Comparison

`equals`

A method to check the equality between two objects (a == b). a ~= b is generated from this one.

`lessthan`

A method to check that a < b. a > b is generated from this one.

`lesseqthan`

A method to check that a <= b. a >= b is generated from this one.

Bitwise "magic"

`binand`

A method to do a binary AND operation between two objects (binand(a, b)).

`binor`

A method to do a binary OR operation between two objects (binor(a, b)).

`binxor`

A method to do a XOR operation between two objects (binxor(a, b)).

`binnot`

A method to negate (~) this object.

`shiftl`

A method to bitwise shift this object left by N bits.

`shiftr`

A method to bitwise shift this object right by N bits.

Iteration

`pairs`

A method that returns a alternative implementation of the pairs iterator for this object.

`ipairs`

A method that returns a alternative implementation of the ipairs iterator for this object.

Other

`tostring`

A method to convert this object to string. tostring(x) = x:tostring().

`concat`

A method for concatenating objects. a .. b = concat(a, b).

`length`

If some code gets the length of this object by using #object, this method is invoked.

`call`

If this object is invoked as a function, the call method is invoked with the arguments given.

AdamWagner / luaclass