Lazarus Documentation Editor

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Good, comprehensive documentation is an important missing part of Lazarus. To help produce the needed documentation a tool called LazDE has been developed. This page describes the use of this tool to edit existing documentation or to create new documentation files. In this wiki document I use [$LazDir] to denote the Lazarus base directory. So when you read [$LazDir] simply replace it with the directory appropriate for your Lazarus installation.

The Rationale

The primary goal of this documentation project is to make available an online help file. To make the help file platform-independent we use XML files to record and store documentation data. Each Lazarus unit has its own XML documentation data file. So far only the units dialogs.pp and buttons.pp have been started with dialogs.xml and buttons.xml being written to document these two units.

Once a decent bank of XML-files has been written, we will then used them to create HTML-pages which can be accessed through the Internet at . Then at a later stage an integrated help system will be developed based on the same XML files as the source for the documentation data.

The Start

As mentioned above, to keep the documentation platform-independent XML is used as a data format. The current documentation can be found in [$LazDir]/docs/xml/. So far the /lcl/ directory contains mainly empty skeleton files, which contain little (or no) useful documentation . The XML files you find in this directory are auto- generated and need to be adapted to be useful. So now we know where to find the files, let's look at the tool which creates and adapts them.

The Tool

"Lazde" is a tool designed to edit the xml documentation files. It can also be used to generate the basic files from source files and (by means of the external tool fpdoc) to generate an HTML version of the documentation. An example of fpdoc output can be seen here, a part of the documentation so far. Since compiled executable versions of lazde are not provided, you have to build one yourself. The sources for "lazde" can be found in [$LazDir]/doceditor/. When you build and run this program, if you open [$LazDir]/docs/xml/lcl/dialogs.xml you will be presented with this screen


The Work


Opening the "Packages" node shows the "LCL" node which contains a "Dialogs" node. Selecting this last node will fill the lower treeview with elements. These elements list the Constants, Types and Classes defined in the Dialogs.pp unit. Any units used by dialogs.pp are also added as further nodes. Other nodes are added for the properties of a class, the parameters of functions and procedures, and so on.

Selecting a node in the lower left treeview displays the content of that node on the right side of the window.

When you look at this page you see an overview of classes defined in the "dialogs" unit. After each class you see a line of text. This text is what was entered in lazde's "short" editbox.

Below the "short" editbox, there is a memo field where you can enter a longer description of the component or property.

Note: If you want to insert a line break use <br/>

Below the main description field are further fields labelled "Errors", "See also" and "Example code File".

"Errors" can be used to tell about errors raised by a function if parameters have values that are out of range. For an example see this page.

The "See also" and "Example code File" fields are each provided with three buttons ([+], [^], [-]). These buttons enable you to add and remove links to other pages or code examples respectively.

The Outcome

Have a look at the description of InputQuery. At the top of the page you can see what the page is about (in this case the InputQuery function from dialogs.pp). The first line of text is what has been entered in the "Short" editbox in lazde.

Next is the declaration of this function taken from the source file dialogs.pp. The declaration part is created by the html-builder and is parsed directly from the sources. Because there are two versions of this function the source position says 0.

Then the arguments are given. When you open the InputQuery node in lazde you will see each argument separately as a child node. The text shown after each argument corresponds to whatever was entered in the "Short" editbox when the respective child node was selected.

The function result is shown as a fourth paragraph. The text shown here has been entered in the same way as for the function's arguments.

Lastly the description is shown. This is the text entered in the description box of lazde.

The addition of new units

There are of course other units that need to be documented. If it is for instance a unit for some package, chances are there is no xml file to start with. You have to start from scratch then, but lazde has a function to get you off to a flying start. Just go to File -> New and the following screen will appear:


You start by giving the package a name. All units you want to add to this package should have the same package name. Afterwards you enter the source file to use; you can browse to this file as well. Then enter a name for the output file. (Do not forget the xml extension!) And press OK.

lazde will then generate the basics for the documentation. The generated file will be opened and the treeview will be populated by all units, classes, types, functions and so on from your source file. Now you are ready to start documenting a new part of Lazarus.

Have a look at LCL Documentation Roadmap to see which units still need to be documented.

You can use FPDoc Updater to easily update FPDoc files when Pascal units have been changed.

The Final result

What I experienced during the use of the program is that I would like to see how the information is shown in its final stage (as a browsable document). For this purpose lazde makes use of a utility to build all necessary HTML-files.

This utility can be started from the menu Extra -> Build. The following screen will be shown:


"Package" should be the same as the name you gave when you created the xml files. For "Format" choose HTML. At "Output" you enter the path where the resulting files should be placed. Press "Add all" and all documents your were working on will be added to the project. Then go to the next to tab


and enter the paths to the source files. After you have pressed build your HD will start to rattle and finally the following output will be shown on the "Build output" tab.

Building docs using command: fpdoc --package="LCL"
--output="/home/matthijs/documentatie/LCL" --format=html --content 

FPDoc - Free Pascal Documentation Tool
(c) 2000 - 2003 Areca Systems GmbH / Sebastian Guenther,

Writing 2788 pages...
Documentation successfully built.

When you go to the directory you entered at "Output" you will see a index.html file and (in this case 4) sub directories. Open index.html in your favorit browser and see the result of all your hard work on the documentation. You will be able to follow the links and read it all.

When you plan to continue working on this package of documentation, press "Save" and save the build options. You will be asked to provide a name for the file and the options will be saved. Next time you want to build the HTML-files you can just "load" them again.

The Submission

When you are satisfied with your work you certainly want to share it with the Lazarus community. All you have to do is make a patch, zip this and send it in.

A small note

Note the following: The lazde is work in progress. It is workable, but not completely finished yet. So there can be some bugs in it, but feel free to fix them.