> Cross platform (mostly). Linux (main target), Windows (experimental), Mac.
So, it is not targeting _terminals_ (like traditional libraries do, including ncurses), it is targeting entire operating systems. That suggests it might be relying on things it shouldn't be relying on, and possibly making a bunch of simplifying assumptions. Given that it also says:
Even terminal programs that just write to stdout depend on the OS to some extent.
On Windows, writing to a terminal window has different effects depending on the type of terminal. The classic Windows Console doesn't understand VT codes but there are API calls to do the same things (position cursor, change attributes etc). Recent versions of Windows Console can be told to understand VT codes, but require an API call to enable VT interpretation, then they understand a subset. Windows Terminal isn't the same as Windows Console. Then there's running things under Mintty, or Cygwin Terminal. Control+C behaves differently under those than under the Windows Console. Then there's running things under "winpty" in a Cygwin Terminal, which uses a hidden Windows Console and translates the resulting character matrix as best it can to terminal codes. There are other terminal emulators too.
Linux terminals have a lot of diversity regarding which VT codes they interpret, but at least there's a common subset for most of them. There's also some variation about codes for keypress, such as modifiers with function keys.
If it uses terminfo or termcap to work with various terminals, there are some OS dependencies regarding what capabilities are likely to be indicated.
The color capability varies. Sending 24-bit color to some terminals will not have the desired effect on others.
Unicode support varies among terminals, and this toolkit uses plenty of Unicode in the demos: Radio buttons, check boxes, box drawing characters, and the bar graph demo. What counts as a wide character (two cells) also varies.
Author of FTXUI here. Thanks for this answer! This is exactly the right reasons.
Every terminal compatible with the main subset of the various VT specifications should be compatible with FTXUI. If someone can prove this wrong, I must fix this ;-)
I own a Linux machine so this is the "main" target. Support is quite strong.
However, I don't own a Windows machine and it's quite painful for me to test on it. Windows support has been added by contributors mostly. That's the reason I say it is still "experimental". The various Windows terminal requires some Windows specific calls to enable VT interpretation, as explained above.
FTXUI can be compiled toward WebAssembly and executed against xterm.js terminal. This proves you can use FTXUI against a compliant terminal and not really depends on OS calls.
https://arthursonzogni.com/FTXUI/examples/
First, I suggest you try to use terminfo to properly ensure your terminal supports the "main subset" you've mentioned.
Second, I suggest you get in contact with Thomas E. Dickey, the maintainer of libncurses and terminfo, to see how he tests that library - on something like 15 different platforms.
Finally, over time, consider relaxing your set of terminal requirements - either with workarounds or with limitation of functionality for less-capable terminals.
I guess that working with more primitive terminals would make easier to use to drive UIs on embedded targets. The "terminal" Ftxui sees becomes just some LCD-painting primitives.
> That suggests it might be relying on things it shouldn't be relying on,
why ? If I have a choice between using a software that works on mac / win / linux, and one that works on those three + a ton of obscure architectures / old systems I'd definitely choose the first one - every additional platform supported invariably means that :
- you have to give up some features or reimplement them yourself (because you want that feature anyways) thus more possibilities of bugs, e.g. the amount of times I've seen people reimplementing badly some POSIX functions or stuff like clock_gettime on windows
- you have to duplicate code, say DLL / so loading if you have some plugin system (plus a mess of #ifdefs because of shit like macOS having a non-functional pthread_cancel, etc...)
- in some cases this may mean that the program author needs to add some run-time indirections, e.g. to call platform functions, which may have a performance cost.
- most likely the build system will be some terrible autotools mess which has not been updated in 15 years and does need 50 changes before working on a modern linux distro (had that merely a week ago) + a batch script for windows
- maybe some performance / technical improvements / simplifications would not be available because they would break compatibility with whatever EBCDIC IBM platform with two users, thus making the software worse, condemning us to the "state of the art" of the oldest supported platform
> If I have a choice between using a software that works on mac / win / linux, and one that works on those three + a ton of obscure architectures / old systems I'd definitely choose the first one
The first option probably means they are assuming the terminal behavior of the common terminal apps desktop users on one of the two/three main platforms are using. But if they're making that assumption, they might as well assume they can use a proper GUI and go with that.
The whole point of terminal programming is that you live within the abstraction which is the terminal. The fact that you're thinking about _systems_ rather than _terminals_ is the problem.
It's perfectly ok to have your app refuse to run on a terminal which lacks certain capabilities (annoying, but ok): You check for whatever you need from the terminal using Terminfo(https://en.wikipedia.org/wiki/Terminfo), and die gracefully if necessary. What's not ok is saying "Oh, I'm running on Windows, so XYZ must be true about the terminal I'm in, I'll just go ahead and assume that's the case".
Also - what you consider "obscure and esoteric systems", for many other people is just "systems".
I didn't bother to comment on this, but these are my thoughts as well. From briefly looking through the source code, it seems like the only way this library cares about the capabilities of the terminal is just checking if '256' or 'truecolor' is in TERM variable, and that's it.
> The whole point of terminal programming is that you live within the abstraction which is the terminal
I really fundamentally disagree that there is a "whole point" to terminals (or any other kind of things we use when we use computers). They are just tools which are able to perform things and one should really not ascribe any kind of semantic layer to them, as this is always a very very brittle abstraction. Just look at things in terms of what they are able to do, not what they are called.
> Cross platform (mostly). Linux (main target), Windows (experimental), Mac.
So, it is not targeting _terminals_ (like traditional libraries do, including ncurses), it is targeting entire operating systems. That suggests it might be relying on things it shouldn't be relying on, and possibly making a bunch of simplifying assumptions. Given that it also says:
> No dependencies
I'm even more worried.