Version 2.01 of the
multiple-inheritance class library for Lua has been released.
As the previous version, it offers a class framework along the lines of
C++, including multiple stateful base classes (not just interfaces)
plus shared (C++ virtual) derivation.
This version supports named classes and using the dot notation for
scoping, and is backwards compatible with the previous 1.03 version
which only supported unnamed classes and square-bracket scoping.
Example of the new style with global named classes and dot scoping:
require
'classlib'
class.Account()
-- declares global var 'Account', see doc.
function
Account:__init(initial)
self.balance = initial or 0
end
function
Account:deposit(amount)
self.balance = self.balance + amount
end
function
Account:withdraw(amount)
self.balance = self.balance - amount
end
function
Account:balance()
return self.balance
end
class.NamedAccount(shared(Account))
-- shared base
function
NamedAccount:__init(name, initial)
self.Account:__init(initial)
self.name = name or 'anonymous'
end
class.LimitedAccount(shared(Account))
-- shared base
function
LimitedAccount:__init(limit, initial)
self.Account:__init(initial)
self.limit = limit or 0
end
function
LimitedAccount:withdraw(amount)
if
amount > self:balance() then
error 'Limit exceeded'
else
self.Account:withdraw(amount)
end
end
class.NamedLimitedAccount(NamedAccount,
LimitedAccount)
function
NamedLimitedAccount:__init(name, limit, initial)
self.Account:__init(initial)
self.NamedAccount:__init(name)
self.LimitedAccount:__init(limit)
end
--
widthdraw() disambiguated to the limit-checking version
function
NamedLimitedAccount:withdraw(amount)
return self.LimitedAccount:withdraw(amount)
end
myNLAccount
= NamedLimitedAccount('John', 0.00, 10.00)
myNLAccount:deposit(2.00)
print('balance
now', myNLAccount:balance()) --> 12.00
myNLAccount:withdraw(1.00)
print('balance
now', myNLAccount:balance()) --> 11.00
myNLAccount:withdraw(15.00)
--> limit exceeded
For full documentation and source
please look at the wiki:
http://lua-users.org/wiki/MultipleInheritanceClasses
or at LuaForge:
http://luaforge.net/projects/luamiclasses/
Any comments or bug reports will be appreciated, thanks.
Hugo Etchegoyen