# Algorithm Wiki

### Site Tools

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# Creating algorithms

## Including an algorithm in a page

An algorithm is stored in a single page in the Algorithm namespace. Different variants require different pages. For example Factorial recursive and Factorial iterative.

You include an algorithm on a different page using the algorithm tag. The last part of the tag is the title of the algorithm page.

[algorithm Fisher-Yates shuffle]

This transcludes the algorithm from Fisher-Yates shuffle.

## Creating an algorithm page

An algorithm page is split into three sections: algorithm, support, and visualisation. Each of these sections contains code wrapped in <syntax> tags.

The basic outline of an algorithm page should look like this:

[algorithm my-algorithm]

====== Algorithm ======
<syntax js>
</syntax>

====== Support ======
<syntax js>
</syntax>

====== Visualisation ======
<syntax html>
</syntax>

The algorithm page should include itself, so that you can easily preview how your changes will work.

### Algorithm

The 1st section contains the algorithm. This is the code that the user sees in the interactive environment.

### Support

The 2nd section contains the support code. This is support code, such as functions that the main algorithm uses. If it also includes a run() function this function is called when running the algorithm.

### Visualisation

The 3rd section contains the visualisation code. This code is a self contained webpage, it is embedded in an i-frame when displayed alongside the code.

The webpage must provide a global update() function, which is called at each new line when running the algorithm. The update function takes two arguments, the current node in the AST and an execution context.

Two other functions are optional: globals() and args(). If the visualisation contains a function args() then the return value of calling that function will be passed into the run support function. This allows the visualisation to supply the input to the algorithm. If a globals function is provided then it returns an object whose keys are added to the globals of the interpreter.

If the body tag has a height style attribute that size is used to size the visualisation.