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Introduction to RDL Core Elements

Here we will describe the core of Research Description Language. How to extend this functionality is described elsewhere.


Including other documents

The include element can be used to insert code from another document at a specified place. The src attribute contains the location of the other document. Supported formats are RDL, SVG, and MathML, as well as graphics formats like JPEG.

The experiment element does an implicit include.


Including data from an experiment

In the end, doing science is all about experiments that falsify or lend support to theories. For this reason, RDL makes a rather big point of using experimental data in RDL documents. The experiment element is key here.

The experiment element has a src attribute that contains the location of the EDL document that describes the experiment. The dest attribute defines a conversion program that creates an RDL document from a given EDL document. The resulting RDL document is then included in the referring RDL document.

Note that elements containing the experiment element may affect the way the conversion takes place. For example, the figure element may force a certain axis range, so that figures can be easily compared.



Figures in an RDL document are represented in Scalable Vector Graphics (SVG). That is, the figure element may contain an svg element that defines its contents. The SVG namespace (http://www.w3.org/2000/svg) is not required.

Note that one usually wouldn't want to include SVG code in an RDL document directly. Mostly the SVG code will be included by an experiment element, using dest="figure".

The figure element may contain information about an axis using the axis element. Its type attribute may contain either x or y. The begin and end attributes indicate the range of the axis. Other usefull attributes are ticks and caption. Any structure that is imposed on the figure using axis elements, is supplied to the edl2rdl-figure tool, that creates SVG code from the output in an EDL document, so that it can make a figure with the requested characteristics.

One can use this feature to make figures comparable. When the compare attribute of a figure element refers to some other figure's id, the referring figure will copy the information in any axis element in the referred to figure, as well as the size of the figure itself. An example is shown below:

<figure id="exponential" width="5cm" height="5cm">
  <axis type="x" caption="Time (generations)" begin="0" end="25"/>
  <axis type="y" caption="Population size" begin="0" end="1400"/>
  <experiment src="exponential.edl" dest="figure"/>
<figure compare="exponential">
  <experiment src="logistic.edl" dest="figure"/>


Mathematical formulas are marked up using MathML. In other words, some RDL element may contain a math element that will be rendered as MathML. The MathML namespace (http://www.w3.org/1998/Math/MathML) is not required.

Tables are marked up using MathML as well.


Referring to other parts of a text