I've not digged into LaTeX3 details described here, but however let me drop a line expressing what I consider the No1 necessity for LaTeX in this moment (maybe LaTeX3 considers this already, but in case it doesn't, please think about it).
While extending LaTeX power and flexibility is highly desirable, there's an even more desirable thing: being able to use it in future OSs. The newest mobile OSs encourage sandboxing and "simple packaging" of applications (ie: all the application code in a big executable, or at least in a compact directory structure which the user can install in whatever place in the file system, without using any system variables for paths configuration).
I wished to use LaTeX on iOS. However, after searching, I found people who tried it, and who concluded that it was technically impossible because of how the LaTeX code is designed.
Moreover, I believe the concept of "LaTeX distribution" is not what the future wants: If somebody has an idea designing an application which in turn uses LaTeX, requesting the user to install a LaTeX distribution before installing the application is unreasonable nowadays (it was reasonable in the past, but it isn't nowadays, and I guess it won't be in the future either).
If some user wants to try an application, and you explain him to install a LaTeX distribution first, chances are that he will avoid trying you application, and will try another one. He expects to just download your app, drop it in his device and just start using it.
Because of this, and because of how mobile OSs are designed nowadays (a design that is also changing and affecting desktop OSs), I believe the best way of implementing LaTeX in the future would be through a single-packaged library which doesn't need to be "installed" and can work in whatever directory you put it. Additional third-party packages could go in a sub-directory next to where the library resides. For being able to continue using LaTeX from the terminal shell, there could be an executable which links to the library, and provides such shell commands.
And, while any open source license would be fine, if the future goes towards simple packaging, MIT-like licensing will provide more success than LGPL-like licensing (just as an example, SDL has moved from LGPL to MIT-like just because of giving more freedom of use in mobile devices which encourage static linking).
Of course it's just my opinion -and perhaps LaTeX3 is considering all this already-, but although it's an opinion, I believe this is what the future wants.
Cheers,
Sonny
General ⇒ Future LaTeX Versions on future Operating Systems
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