Module:Example

local p = {}; --All Lua modules on Wikipedia must begin by defining a variable

                   --that will hold their externally accessible functions.
                   --Such variables can have whatever name you want and may 
                   --also contain various data as well as functions.

p.hello = function( frame ) --Add a function to "p".

                                       --Such functions are callable in Wikipedia
                                       --via the #invoke command.
                                       --"frame" will contain the data that Wikipedia
                                       --sends this function when it runs. 
                                -- 'Hello' is a name of your choice. The same name needs to be referred to when the module is used.
   
   local str = "Hello World!"  --Declare a local variable and set it equal to
                               --"Hello World!".  
   
   return str    --This tells us to quit this function and send the information in
                 --"str" back to Wikipedia.
   

end -- end of the function "hello" function p.hello_to(frame) -- Add another function local name = frame.args[1] -- To access arguments passed to a module, use `frame.args` -- `frame.args[1]` refers to the first unnamed parameter -- given to the module return "Hello, " .. name .. "!" -- `..` concatenates strings. This will return a customized -- greeting depending on the name given, such as "Hello, Fred!" end function p.count_fruit(frame) local num_bananas = frame.args.bananas -- Named arguments () are likewise local num_apples = frame.args.apples -- accessed by indexing `frame.args` by name (`frame.args["bananas"]`, or) -- equivalently `frame.args.bananas`. return 'I have ' .. num_bananas .. ' bananas and ' .. num_apples .. ' apples' -- Like above, concatenate a bunch of strings together to produce -- a sentence based on the arguments given. end

local function lucky(a, b) -- One can define custom functions for use. Here we define a function 'lucky' that has two inputs a and b. The names are of your choice. if b == 'yeah' then -- Condition: if b is the string 'yeah'. Strings require quotes. Remember to include 'then'. return a .. ' is my lucky number.' -- Outputs 'a is my lucky number.' if the above condition is met. The string concatenation operator is denoted by 2 dots. else -- If no conditions are met, i.e. if b is anything else, output specified on the next line. 'else' should not have 'then'. return a -- Simply output a. end -- The 'if' section should end with 'end'. end -- As should 'function'.

function p.Name2(frame) -- The next five lines are mostly for convenience only and can be used as is for your module. The output conditions start on line 20. local pf = frame:getParent().args -- This line allows template parameters to be used in this code easily. The equal sign is used to define variables. 'pf' can be replaced with a word of your choice. local f = frame.args -- This line allows parameters from to be used easily. 'f' can be replaced with a word of your choice. local M = f[1] or pf[1] -- f[1] and pf[1], which we just defined, refer to the first parameter. This line shortens them as 'M' for convenience. You could use the original variable names. local m = f[2] or pf[2] -- Second shortened as 'm'. local l = f.lucky or pf.lucky -- A named parameter 'lucky' is shortend as l. Note that the syntax is different from unnamed parameters. if m == nil then -- If the second parameter is not used. return 'Lonely' -- Outputs the string 'Lonely' if the first condition is met. elseif M > m then -- If the first condition is not met, this line tests a second condition: if M is greater than m. return lucky(M - m, l) -- If the condition is met, the difference is calculated and passed to the self defined function along with l. The output depends on whether l is set to 'yeah'. else return 'Be positive!' end end

return p --All modules end by returning the variable containing their functions to Wikipedia. -- Now we can use this module by calling Hello World!, -- Hello, foo !, or I have 5 bananas and 6 apples -- Note that the first part of the invoke is the name of the Module's wikipage, -- and the second part is the name of one of the functions attached to the -- variable that you returned.

-- The "print" function is not allowed in Wikipedia. All output is accomplished -- via strings "returned" to Wikipedia.