unwrap-mml

Library to convert simple MathML equations to XML/plaintext

Description

Besides LaTeX, MathML is in most cases the preferred format for the markup of math equations. However, simple equations and formula symbols do not necessarily need to be presented as MathML. In certain scenarios, it's more convenient to render the equations as plain text, for example to accelerate the rendering of the document, to decrease file size or to bypass lacking MathML support in some reading systems (poor you!).

How it works

Common math styles (bold, italic, bold-italic) and superscripts and subscripts are tagged with the appriopriate elements of the document XML schema. Letters in other styles (e.g. double-struck, fraktur, script) are mapped to their Unicode equivalent.

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <msup>
    <mi>x</mi>
    <mn>2</mn>
  </msup>
</math>

The expression above converted to XHTML:

<i>x</i><sup>2</sup>

You can find the full examples here.

Configuration

Create an XSLT stylesheet and import xsl/unwrap-mml.xsl.

<xsl:import href="unwrap-mml.xsl"/>

Override the following parameters (XSD type: element()) to create appropriate wrapper elements for your target XML grammar:

• wrapper (wrapper for the entire equation)
• superscript
• subscript
• bold
• italic
• bold-italic

Here is an example on how to configure that MathML superscripts are replaced with DocBook superscripts:

<xsl:param name="superscript" as="element()">
  <superscript xmlns="http://docbook.org/ns/docbook"/>
</xsl:param>

Note: If you want to convert MathML to pure plaintext, just declare all parameters as empty.

Use the function tr:unwrap-mml-boolean() as condition in your template to determine whether the MathML can be unwrapped or not. Apply subsequent templates in the XSLT mode unwrap-mml.

<xsl:template match="*:inlineequation[mml:math[tr:unwrap-mml-boolean(.)]]">
  <xsl:apply-templates mode="unwrap-mml"/>
</xsl:template>

You can configure at which size an equation won't be unwrapped. Therefore, you can set a limit for the maximum numbers of operators. If an equation has more operators than the operator limit, it won't be unwrapped. Please note that the operator limit represents <mo>s except those which contain parentheses or just whitespace.

<xsl:param name="operator-limit" select="1" as="xs:integer"/>

Note: unwrap-mml requires that MathML comes with the namespace URI http://www.w3.org/1998/Math/MathML. If this is not the case, you must attach the namespace first and then invoke unwrap-mml. You can find an example in xsl/unwrap-mml-aplusplus.xsl