https://youtu.be/5Fcl56--VJ4

https://youtu.be/TNwodosMR44

https://youtu.be/rU94hEGOJxM

https://youtu.be/-_dunq3BAbM

https://youtu.be/qdlPcF-z1ug

and the TeXmacs source files are there : 

https://cahier-de-prepa.fr/mpsi-kju/docs?rep=176

 very nice videos! can we add them to the list of TeXmacs videos we maintain on youtube? 

Now, what I’d like to say is that there is a steep learning curve with TeXmacs, even if you’re not computer illiterate.

It would make sense to make TeXmacs my first choice when editing scientific documents, but I am still facing many walls.

It would be very useful to have an idea of the difficulties and the concepual wall that a beginner user faces, this would allow us to write better tutorials. Can you explain the stumbling blocks you faced?

An example of difficulty I just encountered and for which I was about to ask for help here : starting from a blank document and inserting a session, be it python or scheme, I wondered how to terminate the session to go back to normal editing, then why not a bit later in the document entering a new session but… close session just terminated the process and I still had a python or a scheme prompt, and typing anything just restarted the process… (according to the documentation, this is not a bug, but a feature, and I understand why it makes sense)

I'm not sure what you mean: kill the process or just go on with the text? In the second case I just position the cursor with the mouse after the session and continue writing. I'm sure there is an appropriate command, but it works for me just as well.. 

Being with a mac keyboard it took me a very long time to find out that I had to page-down (which doesn’t exist per se on a mac keyboard) to allow to the cursor to go outside the session… Try it with a mouse and not using page-down and you’ll understand I guess my frustration...

No it is easy: just click on the right margin, out of the session, the cursor will position just after the session, then you can press enter and continue writing norma text. Did I understood your difficulty correclty?

So there comes my question : Joris often redirects users to the Jolly Writer for further reference, and I guess it might be a good read for me, as well as for my students (it could be a good alternative to beamer for their presentations) so I suggested our librarian to order one. I might want to have one except it is expensive and this is the kind of document I would much rather read on my iPad or the screen of my computer than on paper.

For a pdf, maybe watermark protected, I would be willing to pay a good 20 euros… (but maybe not 49…)

My opinion on this matter is the following:

1) Bundled with TeXmacs there is a substantial user manual (280 pages) which contains all the basic features, there are some tutorial on the web page too, and a lot of videos on youtube. In my experience people do not take time to even look at the user guide before giving a try. The problem is that TeXmacs is designed very differently wrt. a usual text editor so the user is confused by his\her expectations.

2) The book Joris wrote (TJW) is very well written and of quality. I've just checked on amazon and books on LaTeX (e.g. Lamports') sell in "Broché" form at 49 euros, and other books are at 30 always in "Broché". So I feel the price for TJW is more than fair in my opinion. It is not the only source for information and to me should be considered as a reasonable way to show support for the project. Essentially there is several people which spend time on this and Joris is the one which spend (by far) the larger amount of time on developing and making TeXmacs better (and removing the bugs I put in...). You can check on savannah the commit log to get an idea of the amount of programming time TeXmacs requires. 

Maybe have a PDF is reasonable, but I'm not sure people would like to spend 20 euros on a file and not 50 of a high quality (and heavy :)) book. 

3) I should say, I'm reading TJW since few months and I find really pleasant, it is way more than a manual, and discuss general problem of creating beautiful technical documentations in many aspects.

Would Joris consider letting us buy a pdf instead ?

Maybe he should consider to distribute it via the Apple Store Books or on the Kindle. I doubt a PDF can be protected against copy. (go to libgen and see for yourself :))