[Lua]表驱动索引编程，form.lua

form.interface

local form = {_tag = 'form'}
function form.build(tag, super)
--[[
    -- form to produce the target with super functional table and integrating multi-interface implement feature
    -- produce a target and hold following feature
    target:spec(interface) -- integrating the interface feature
    target:spec(name, property) -- property holder
    target:on(other) -- binding feature to other target and produce a delegater
--]]end

function form.on(target, spec)
--[[
    -- produce a delegater binding target feature with itself from spec, that the feature defined in spec
--]]end

function form.spec(target)
--[[
    --attach a form feature to the target

    --if target builded from `form.build`
    function target:spec(interface)
        -- specify target reuse interface code
    end
    --following feature is flexible
    function target:spec(prop, target)
        -- specify target property initial value and produce getter/setter
        -- example
        -- target:spec('prop', property)
        -- target:prop() return the property
        -- target:prop(property) to set the property
        -- target:spec('feature', interface)
        -- target:spec('feature') return the interface delegater binding on the target
    end

    -- if target is a interface implementation of a certain specification
    local spec = target
    function spec:on(target)
        -- produce the interface delegater binding on the target from spec
    end
--]]end

 查看实现代码：form.lua

form.test

local form = require('form')
-- 接口定义
local spec = {_tag = 'sepc'}
function spec:Show(msg)
    print(self._tag..':Show(msg) not implemented')
end
function spec:Dependence(target)
    print(self._tag..':Dependence(target) not implemented')
end
function spec:noImplementation()
    print(self._tag..':noImplementation() not implemented')
end
-- 接口实现
local port = form.build('spec', spec)
print('
port ###test start---------------------------')
port:Show()
port:Dependence()
port:noImplementation()
function port:Show(msg)
    print('port:Show(msg)...')
    print(msg)
end
print('
overwrite port:Show(msg)--------------------')
port:Show('port:Show using spec.Show')

function port:Dependence(target)
    print('port:Dependence(target)...')
    target.Show('DI, Dependence Input; implementation binded on '..target._tag..' from port')
end
print('
port ###test over---------------------------')


-- 派生复用
local target
    = form.build('target'--[[, port]]) -- 可从#super 派生复用
        :spec(port)-- 可指定接口形式复用

print('
target ###test start---------------------------')
target:noImplementation() -- spec:noImplementation()
target:Show('target:Show using port.Show') -- port:Show(msg)

print('
Depend on [port] implement---------------------')
local tar_ = port:on(target)-- binding on target, implementation from port
tar_.Show('tar_.Show()')
print('
target:Dependence(tar_) using port:Show(msg)---')
target:Dependence(tar_) -- port:Dependence(target)

print('
overwrite target:Show(msg)---------------------')
function target:Show(msg)
    print('target:Show(msg)...')
    print(msg)
end
print('
target:Dependence(tar_) using port:Show(msg)----')
target:Dependence(tar_)

print('
Depend on [target] implement--------------------')
print('
target:Dependence(tar_) using target:Show(msg)--')
tar_ = form.on(target, port)-- using target implementation spec from port
tar_.Show('tar_.Show()')
target:Dependence(tar_)
print('
target ###test over-----------------------------')

 form.lua提供友好的lua协约式编程form，完整满足以下两点

• 派生复用机制
• 面向接口特性

form.test 运行成功。后续将给出Lua协约式编程范例；基于form.lua实现通知订阅方式