OOP – Lua – Try calling method ‘new’ (zero value)

module(..., package.seeall)
require'middleclass'

Person = class('Person');
function Person:initialize(name)
 self.name = name;
 print(" INITIALIZE: ".. self.name);
end

function Person:speak()
 print('Hi, I am '.. self.name ..'. ')
end

require'Person'

local testPerson = Person:new("Sally") 
testPerson:speak()

require'middleclass.init'

Person = class ('Person')

function Person:initialize(name)
 self.name = name
 print("INITIALIZE: ".. self.name)
end 

function Person:speak()
 print('Hi, I am '.. self.name ..'.')
end

./main.lua
./Person.lua
./middleclass/init.lua
. /middleclass/middleclass.lua

Novice to Lua, trying to figure out how to use middleclass library for OOP

main.lua:

require'middleclass'
requir e'Person'

local testPerson = Person:new("Sally"); //causes Runtime error: attempt to call method'new' (a nil value)
testPerson:speak( );

Person.lua:

module(..., package.seeall)
require'middleclass'
< br />Person = class('Person');
function Person:initialize(name)
 self.name = name;
 print("INITIALIZE: ".. self.name); 
end

function Person:speak()
 print('Hi, I am '.. self.name ..'.')
end

Why do I receive this error?

First of all, the semicolon at the end of the line is not necessary, it may be a bad habit of writing Lua code. Secondly, I changed the requirement of’middleclass’ in two The file needs’middleclass.init’ and the module (…, package.seeall) is deleted. After that, the sample code works normally on my machine using Lua 5.1.4.

main. lua

require'Person'

local testPerson = Person:new("Sally")
testPerson:speak()

Person.lua

require'middleclass.init'

Person = class('Person')

function Person:initialize(name)
 self.name = name
 print("INITIALIZE: ".. self.name)
end

function Person:speak ()
 print('Hi, I am '.. self.name ..'.')
end

You may directly include the middleclass.lua file. There is no setting to this Work in this way. The purpose is to include middleclass/init.lua.

If you use these two files exactly as shown above and lay out the files as shown below, you can use it.

./main.lua
./Person.lua
./middleclass/init.lua
./middleclass/middleclass.lua