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Module:Example

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--- Example module.-- @module example-- @alias plocalp={}--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.--- Hello world function-- @param {table} frame current frame-- @return Hello worldp.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.localstr="Hello World!"--Declare a local variable and set it equal to--"Hello World!". returnstr--This tells us to quit this function and send the information in--"str" back to Wikipedia.end-- end of the function "hello"--- Hello world function-- @param {table} frame current frame-- @param {string} frame.args[1] name-- @return Hello worldfunctionp.hello_to(frame)-- Add another functionlocalname=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 modulereturn"Hello, "..name.."!"-- `..` concatenates strings. This will return a customized-- greeting depending on the name given, such as "Hello, Fred!"end--- Counts fruit-- @param {table} frame current frame-- @param {string} frame.args.bananas number of bananas-- @param {string} frame.args.apples number of apples-- @return Number of apples and bananasfunctionp.count_fruit(frame)localnum_bananas=tonumber(frame.args.bananas)or0-- Named arguments ({{#invoke:Example|count_fruit|foo=bar}})localnum_apples=tonumber(frame.args.apples)or0-- are likewise accessed by indexing `frame.args` by name (`frame.args["bananas"]`,-- or equivalently `frame.args.bananas`.localconj_bananas=num_bananas==1and'banana'or'bananas'localconj_apples=num_apples==1and'apple'or'apples'-- Ternary operators assign values based on a condition in a compact way.-- Here, `conj_bananas` gets `'banana'` if `num_bananas` is 1, else `'bananas'`.-- Similarly, `conj_apples` gets `'apple'` if `num_apples` is 1, else `'apples'`.return'I have '..num_bananas..' '..conj_bananas..' and '..num_apples..' '..conj_apples-- Like above, concatenate a bunch of strings together to produce-- a sentence based on the arguments given.end--- Lucky function-- @param {string} a-- @param {string} b-- @return Whether a is lucky.localfunctionlucky(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.ifb=='yeah'then-- Condition: if b is the string 'yeah'. Strings require quotes. Remember to include 'then'.returna..' 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'.returna-- Simply output a.end-- The 'if' section should end with 'end'.end-- As should 'function'.--- Name2-- @param {table} frame current frame-- @return Some outputfunctionp.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 50.localpf=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.localf=frame.args-- This line allows parameters from {{#invoke:}} to be used easily. 'f' can be replaced with a word of your choice.localM=f[1]orpf[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.localm=f[2]orpf[2]-- Second shortened as 'm'.locall=f.luckyorpf.lucky-- A named parameter 'lucky' is shortend as l. Note that the syntax is different from unnamed parameters.ifm==nilthen-- If the second parameter is not used.return'Lonely'-- Outputs the string 'Lonely' if the first condition is met.elseifM>mthen-- If the first condition is not met, this line tests a second condition: if M is greater than m.returnlucky(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'.elsereturn'Be positive!'endendreturnp--All modules end by returning the variable containing their functions to Wikipedia.-- Now we can use this module by calling {{#invoke: Example | hello }},-- {{#invoke: Example | hello_to | foo }}, or {{#invoke:Example|count_fruit|bananas=5|apples=6}}-- 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.
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