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− | A complete tutorial about classes is written here: http://www.inspired-lua.org/2011/05/5-object-classes/ | + | A complete tutorial about classes is written here: http://inspired-lua.org/index.php/2011/05/5-object-classes/ |
| | | |
− | Here's how the class() function is defined, in the API : | + | Here's how the class([parent]) function is defined, in the API : |
| | | |
| <source lang="lua"> | | <source lang="lua"> |
− | -- Class definition system
| |
| class = function(prototype) | | class = function(prototype) |
− | local derived = {}
| + | local derived={} |
− | local derivedMT = {
| + | if prototype then |
− | __index = prototype,
| + | function derived.__index(t,key) |
− | __call = function(proto, ...)
| + | return rawget(derived,key) or prototype[key] |
− | local instance = {}
| + | end |
− | local instanceMT = {
| + | else |
− | __index = derived,
| + | function derived.__index(t,key) |
− | __call = function()
| + | return rawget(derived,key) |
− | return nil, "attempt to invoke an instance of a class"
| + | end |
− | end,
| + | end |
− | }
| + | function derived.__call(proto,...) |
− | setmetatable(instance, instanceMT)
| + | local instance={} |
− | if instance.init then
| + | setmetatable(instance,proto) |
− | instance:init(...)
| + | local init=instance.init |
− | end
| + | if init then |
− | return instance
| + | init(instance,...) |
− | end,
| + | end |
− | }
| + | return instance |
− | setmetatable(derived, derivedMT)
| + | end |
− | return derived
| + | setmetatable(derived,derived) |
− | end | + | return derived |
| + | end |
| | | |
| </source> | | </source> |