Dev meeting – 25th Jan – TCR, NativeScript, Tentai Show and XQuery for IDEA

Chris talked about “Test-Commit-Revert”, an idea from Kent Beck building on TDD. Kent Beck was using a process of “Test, Commit every time that all the tests pass”, so you are never left with a state where the tests used to work and you’re not quite sure why they stopped working. But the extreme extension to that is “Test-Commit-Revert” – commit when the test pass, but revert all your changes if the test fail! This forces you to have a very short commit cycle, making tiny incremental changes each time. It’s even more interesting if you doing it in a team, and everyone is doing this simultaneously, as you each do tiny commits and then build on top of each others changes. Chris (and Kent Beck) aren’t suggesting that we do this all the time, but it’s an interesting idea that makes you think about how your development cycle works.

Alex talked about NativeScript – a way of writing code for mobile devices from VueJS. It isn’t just a web browser shell – it’s very fast. It doesn’t use HTML – instead, it uses “NativeXML” which has a lot more control over Android-style layout. There is a very good short project as the introduction, which is a great place to start and walks through all the basics. Alex showed us a very simple chunk of Vue code and NativeXML that produced a simple application. There is code in his Github account at He recommends it highly for mobile development (the only issues are with the general complexity of the Android ecosystem). We discussed how easy it would be to convert an existing VueJS app to NativeScript – not that easy, since it doesn’t use HTML.

Chris also talked about some code that he wrote over Christmas to solve a Japanese puzzle called “Tentai Show” – this is apparently a pun around astronomy and rotational symmetry. There is a grid of squares, containing stars that are in a corner or in the centre; and you need to divide up this grid into jigsaw pieces that have rotational symmetry. There is an example at Chris wrote a solver for this in Scala, on his Github at

Reece then talked about his XQuery plugin for IntelliJ IDEA. This is available from the JetBrains plugin repository at It supports XQuery 1.0, 3.0, and 3, also with support for MarkLogic and BaseX extensions. At present, he’s working on splitting out the XPath support from XQuery – so the features of his plugin can also be used in XSLT as well. He has already got Run Configurations working for a range of processors including Saxon and MarkLogic, so you can specify which query processor it uses. It’s already the best XQuery plugin available – but there is also a huge set of additional features that he is working on!