encapsulation chapter: lua => DONE

Author: kariminf

book/encapsulation.tex

@@ -86,7 +86,13 @@ \subsection{Javascript}
 
 \subsection{Lua}
 
-%\lstinputlisting[language={[5.2]Lua}, linerange={1-2}, style=codeStyle]{../codes/lua/person.lua}
+Using tables to create objects, all members are accessible outside the class, hence public.
+
+\lstinputlisting[language={[5.2]Lua}, linerange={1-5,7-7,11-12,14-14,17-19}, style=codeStyle]{../codes/lua/encapsulation/person.lua}
+
+You can access them anywhere
+
+\lstinputlisting[language={[5.2]Lua}, linerange={1-6}, style=codeStyle]{../codes/lua/encapsulation/app.lua}
 
 \subsection{Perl}
 
@@ -182,7 +188,7 @@ \subsection{Javascript}
 
 \subsection{Lua}
 
-%\lstinputlisting[language={[5.2]Lua}, linerange={1-2}, style=codeStyle]{../codes/lua/person.lua}
+There is no protected members in Lua, but you can use a naming convention to specify them.
 
 \subsection{Perl}
 
@@ -300,7 +306,15 @@ \subsection{Javascript}
 
 \subsection{Lua}
 
-%\lstinputlisting[language={[5.2]Lua}, linerange={1-2}, style=codeStyle]{../codes/lua/person.lua}
+Using closures, you can create internal fields inside the constructor of an object.
+The functions which access this field must be defined inside the constructor.
+
+\lstinputlisting[language={[5.2]Lua}, linerange={1-6,8-12,19-19}, style=codeStyle]{../codes/lua/encapsulation/person.lua}
+
+You cannot access it outside the class. 
+But, you can create a new public field dynamically, but it will not replace the internal one.
+
+\lstinputlisting[language={[5.2]Lua}, linerange={1-3,7-8}, style=codeStyle]{../codes/lua/encapsulation/app.lua}
 
 \subsection{Perl}
 

codes/lua/encapsulation/app.lua

@@ -0,0 +1,9 @@
+local Person = require "person"
+
+local p = Person.new("Karim_p")
+p:info()
+
+p.luckyNumber = 6
+-- print("name outside= " .. p.name) -- error: nil value
+p.name = "other name"
+p:info()

codes/lua/encapsulation/encap.lua

@@ -0,0 +1,41 @@
+local Index = {
+  local private =  {}
+  local protected = {}
+}
+
+Index.__index = function(self, key)
+  local member = Rectangle[key]
+  if member ~= nil then
+    return member
+  end
+  if key == "w" then
+    return self.width + 2
+  elseif key == "h" then
+    return self.height + 1
+  end
+end
+
+Index.__newindex = function(self, key, value)
+  if string.sub(key,1,2) == "__" then
+
+  elseif string.sub(key,1,1) == "_" then
+  end
+end
+
+local Person = {}
+Person.__index = Person
+
+function Person.new(name)    -- The constructor
+  local self = {}
+  local _name = name;
+  self.luckyNumber = 1;
+  self.info1 = function()
+    print("My name: " .. _name)
+  end
+  return setmetatable(self, Person)
+end
+
+function Person:info()
+  self.info1()
+  print("My lucky number: " .. self.luckyNumber)
+end

codes/lua/encapsulation/person.lua

@@ -0,0 +1,19 @@
+local Person = {}
+Person.__index = Person
+
+function Person.new(name)    -- The constructor
+  local self = {}
+  local _name = name;
+  self.luckyNumber = 1;
+  self.info1 = function()
+    print("My name: " .. _name)
+  end
+  return setmetatable(self, Person)
+end
+
+function Person:info()
+  self.info1()
+  print("My lucky number: " .. self.luckyNumber)
+end
+
+return Person