Translating an expression to MathML: mathml

### 3.7.4 Translating an expression to MathML: mathml

The mathml command translates expressions to MathML.

- mathml takes one argument:
  expr, an expression.
- mathml(expr) returns the result of evaluating expr written in MathML.

Example.
Input:

mathml(1/4 + 1/4)

Output:

`<?xml version="1.0" encoding="iso-8859-1"?>`
`<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN"`
`"http://www.w3.org/TR/MathML2/dtd/xhtml-math11-f.dtd" [`
`<!ENTITY mathml "http://www.w3.org/1998/Math/MathML">`
`]>`
`<html xmlns="http://www.w3.org/1999/xhtml">`
`<body>`
`<math mode="display" xmlns="http://www.w3.org/1998/Math/MathML">`
`<mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac>`
`</math><br/>`
`</body> </html>`

which is the number 1/2 in MathML form, along with enough information to make it a complete HTML document.