Lazarus Examples Window

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This wiki page is an attempt to capture people's thoughts wrt replacing the existing Examples Window in the Lazarus IDE.

Progress Report

March 8th, 2022

  • Compile the above with the usual "make bigide"
  • Start it up, remember to set an alternative config path so not to overwrite your usual Lazarus.
  • in the IDE, go to Package -> Open Package File (.lpk) and browse to where you downloaded to, components/exampleswindow/exampleprojects.lpk and open that, click Use->Install and let i rebuild as usual.
  • In use, there is a menu entry, Tools->Example Projects or in the startup mode with a project loaded, the ProjectWizard has an Example Projects button.

  • Most if not all of the viable examples in Laz-Dir/examples have now been categorized and have a metadata file. Some 104 projects made it through.

Still to do -

  • Process the remaining Examples in the Lazarus Source, about 200 ?
  • Encourage third party package maintainers to add a metadata file if they have examples.NewLazExWin.png

Why is there a problem ?

The existing Examples system has issues, perhaps in that it has not keep up Lazarus's own rapid development. There are a number of issues identified (in no particular order) -

  • Linux Lazarus installs based on (distro) Packages have the Examples in read only space.
  • Most Examples do not have any indication of the topic covered other than file/project name.
  • Examples don't have a category system identifying who target audience is, beginner to advanced user.
  • Many examples are outdated, many don't, for example use the Lazarus Form Designer confusing new users who expect to see Object Inspector content.
  • The system is limited to only those examples shipped in the main Lazarus distribution, cannot cover eg Examples applicable to OPM.

What should the user experience be like ?

  • A user should be able to choose to see content appropriate to their experience.
  • Be able to see a summary of what an Example is about before opening it.
  • Be able to open an Example, have a play with it, make a few changes and recompile to see what happens. Maybe roll back to the original Example if they make a full mess of it.
  • Examples should be generally short, contain appropriate, relevant code focused on one topic each. But there will me many exceptions to that.
  • If a user installs a third party package, eg via OPM, then any examples it contains should be treated in the same manner.
  • Be useful to allow a user to browse through example content while working on a real project, copy and past a snipit as required.

How do we achieve this ?

There appears to be three key steps, reviewing all existing Examples, adding meta data and redesigning the Examples Window is clearly necessary. A reasonably easy to work with metadata standard will ensure ongoing performance. Ensuring that standard is complied with in new Examples may be more than we should ask Lazarus Developers to be responsible for.

Third party packages is a grey area, many do not have examples at all (so be it), some will have Examples that can work with a proposed new system with just the addition of a metadata file. There will be situations where a "forth party" will produce an Example without the cooperation of the package author.

We also need to keep in mind that by distributing, indexing or referring to Examples, we take on some Duty of Care to ensure that no Example contains malicious code and, perhaps, is Fit for Purpose.

That is about all we all agree on at present !


There appears to be two broad models available, each with their own advantages and disadvantages. Choosing one or the other model and determining what our metadata file looks like is the next phase.

Its likely that the metadata design is substantially the same either model.

Both Example Model will require -

  • An extensive review of all existing Examples is required (for both models).
  • Additional of a metadata file.
  • A call for more Examples.
  • A means to scan for 'other' Examples, such as ones in OPM packages.

Examples Remain in Distribution.

This is the KISS solution, it involves the least structural change but may not necessarily involve less work. As well as reviewing and adding meta data, we may wish to re-organize the location of packages.

It would make sense to still move a selected project from its location in the SRC tree to (eg) Lazarus config area to to -

  • Solve the Linux Read Only problem and
  • allow a user who has edited an example project excessively to "roll back" and start again.
  • continuity if the user updates their Lazarus.

The Process is probably to add the meta data to each existing project over time and eventually, when that is all done, alter the existing Lazarus Examples Window to use the new model. The metadata file will aide the existing Lazarus Example Window but will do no harm either.

The down sides of this approach are -

  • An end user cannot browse the Examples (online). They will need to close a project they are working on, find the relevant Example and open it in Lazarus.
  • The changes that must happen to the existing Examples will need extensive Lazarus Developer involvement. Either one very scary diff or lots of somewhat smaller ones.

Examples move on-line

Possibly a simpler change because much of it is implemented externally, at some stage the Examples Window will need to be changed in the Lazarus Distro but lots of building, adjusting of existing Examples, testing can happen without annoying Lazarus Developers.

Prototype code to download files, index projects and build a master metadata file already exists.

A very rough and ready example example repository has been established at

The process would be to complete the metadata and testing of all Examples. Next the existing gitlab tree at under dbannon would move to being under the FPC/Lazarus, finally, the Lazarus Examples Window would change to point to the Examples in the official gitlab tree. At some stage, the existing Examples would be removed from the Lazarus SRC, perhaps leaving a small representative number.

The downsides of this approach -

  • Its a drastic structural change.
  • And end user requires network access to download an Example.

Using the Demo App

Firstly, you can browse the repository, just looking for snipits of code, you can download a particular Example directory as a zip file and use it locally. This is perhaps, for many users, easier than closing their existing project, opening up the example, seeing what they are looking for and going back to their real project and continuing working. But you need online access....

An application now exists that makes creating and managing the metadata files. We'll call it EMT, Example Management Tool, . It will copy a project's files into a ready to push git directory. The process is -

  • Check the default directories in EMT, they are set to suit me, probably not you !
  • In EMT, press the Set button and point to the directory containing the example you plan to test and process. Important you do this before compiling the project otherwise you will be trying to add compiled binary files.
  • Open that project in Lazarus, make sure it works, does what it appears to claim to do and if all OK, fill in the meta data in EMT, if the project has a readme.txt file, use at least some of its content. Click Save.

EMT will also allow you the directly edit a metadata file and save it back where it came from. And it incorporates a draft Lazarus Examples Windows, a prototype of what may go into Lazarus eventually.

The Meta Data File

It has been suggested we need a 'proper' metadata file format, either xml or json. My preference is json and I suggest that an individual example project file would look like this -

"Laz_Hello" : {
    "Category" : "Beginner",
    "Keywords" : ["Lazarus", "Hello World", "TButton", "TMemo"],
    "Description" : "This might be your first Lazarus project, its the traditional Hell World.  Two buttons have been dropped on the form, renamed and their captions set. A memo was then added and each button was double clicked and what they are expected to do was set."

In this case, the example project files would be in a subdirectory called laz_hello, same spelling but all lowercase consistent with Lazarus.

And by extension, the master.ex-meta file, regenerated frequently and downloadable from the repo to be cached locally would look like this -

"LastUpDate" : "2021-10-19T11:44:41+11:00",

"Beginner/laz_hello" : {
    "Name" : "Laz_Hello",
    "Category" : "Beginner",
    "Keywords" : ["Lazarus", "Hello World", "TButton", "TMemo"],
    "Description" : "This might be your first Lazarus project, its the traditional Hello World.  Two buttons have been dropped on the form, renamed and their captions set. A memo was then added and each button was double clicked and what they are expected to do was set.",

"Components/listview" : {
    "Name" : "ListView",
    "Category" : "Components",
    "Keywords" : ["TListView", "grid", "needs work"],
    "Description" : "A project that demonstrates some of a TListView's capabilities. Not so much a \"how to use\" as an exerciser of capabilities. Note, entering an invalid column number triggers a crash."


Note the date in ISO format, overall, the file is still reasonably human readable. And now, of course, its easily extendable. We could add a format version but I don't consider it necessary.

See also