https://github.com/joshtynjala/getset.lua

A simple getter and setter library for Lua.
https://github.com/joshtynjala/getset.lua

corona-sdk lua

Last synced: 4 months ago
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A simple getter and setter library for Lua.

• Host: GitHub
• URL: https://github.com/joshtynjala/getset.lua
• Owner: joshtynjala
• Archived: true
• Created: 2011-09-29T01:39:12.000Z (over 13 years ago)
• Default Branch: master
• Last Pushed: 2011-10-04T06:23:46.000Z (over 13 years ago)
• Last Synced: 2024-05-01T19:33:46.760Z (9 months ago)
• Topics: corona-sdk, lua
• Language: Lua
• Homepage: https://github.com/joshtynjala/getset.lua
• Size: 93.8 KB
• Stars: 11
• Watchers: 5
• Forks: 8
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md

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README

        
# getset.lua

A library for defining getters and setters on Lua tables by [Josh Tynjala](http://twitter.com/joshtynjala).

## Usage

	local getset = require("getset")

	

	function createSimple2DPoint()

		local _x = 0

		local _y = 0

		local point = {}

		getset.defineProperty( point, "x",

		{

			get = function()

				return _x

			end,

			set = function( value )

				_x = value

			end

		})

		getset.defineProperty( point, "y",

		{

			get = function()

				return _y

			end,

			set = function( value )

				_y = value

			end

		})

		

		getset.defineProperty(point, "length",

		{

			get = function()

				return math.sqrt(_x * _x + _y * _y)

			end

			-- no setter required

		})

		

		-- prevents new fields from being added later, and existing fields cannot

		-- be configured (we can't redefine the getters and setters later).

		-- see also: getset.preventExtensions()

		return getset.seal(point)

	end

	

	local myPoint = createSimple2DPoint()

	myPoint.x = 4

	myPoint.y = 4

	

	-- returns 5.6568542494924:

	local myPointLength = myPoint.length

	

	-- runtime error because the table is not extensible:

	myPoint.z = 7 

	

	-- runtime error because length has no setter:

	myPoint.length = 9 

	

	-- runtime error because table is sealed:

	getset.defineProperty( myPoint, "x",

	{

		get = function()

			return 1

		end

	})

	

## API

The getset library offers the following functions. For more detailed descriptions, see the documentation above each function in getset.lua.

### getset.defineProperty( table, key, descriptor )

Defines a getter and a setter on a table for a specific key. Both are optional.

### getset.preventExtensions( table )

Prevents new properties from being added to a table. Existing properties may be modified and configured.

### getset.isExtensible( table )

Determines if a table is may be extended.

### getset.seal( table )

Prevents new properties from being added to a table, and existing properties may be modified, but not configured.

### getset.isSealed( table )

Determines if a table is sealed.