> The real fix requires agreement at the protocol level, across terminal emulators, shell applications, and TUI frameworks simultaneously.
Yeah, and ideally you want the backward compatibility, so we don't have to recompile the world or patch things like e.g. cat.
But yeah, the root of the problem is that a) the TUI-like application that manually drives the terminal, with cursor movement/line folding/redrawing etc. needs to know, at every single moment, the precise location of the cursor and the coordinates of every single character it outputted (to e.g. properly handle backspacing, including over the line folds: \b explicitly doesn't move to the previous line by default and very wide and old convention), and b) getting that coordination info from the terminal in quick, reliable, and side-effect free manner is impossible, so you have to guess.
Like [0] that Windows has for its console? This API has just recently finally lost to UNIX's in-line signaling, because the in-band controls can be proxied through almost anything, including literal serial line with two RX-TX wires and a common ground; the downside, of course, is that you have to build "out-of-line" signalling on your own.
If getting the current cursor position in the terminal were as easy (and as fast) as calling GetConsoleScreenBufferInfo, instead of sending "\e[6n" to the terminal and then reading input from it and looking for "\e[(\d+);(\d+)R" inside and then somehow unreading the input before that device report, yeah, that'd be nice and would allow solving a lot of problems with mere brute force. Sadly, it is not, and so most reimplementations of e.g. readline/linenoise functionality in shells and prompts (Erlang's shell went through 2 internal reimplementations just in my time using it, for example) are flying blind, hoping that their implementation of wcwidth(3) matches the terminal's one.
The issue is handled both by Emacs and Acme by eschewing the terminal. Instead they use the shell (and direct command execution) for commands. So that means no terminfo/termcap, ncurses, and escape codes (but Emacs have a library to parse some ansi codes).
How often are complex scripts rendered in terminal? What is the cost to scripts that are currently rendered accurately by terminal? Are there any group of tools that operate in complex scripts?
EDIT: Without saying that I think this is worthy and cool. I am just curious about the costs and benefits of such a tool.
> How often are complex scripts rendered in terminal?
If you speak the languages that use those scripts? Then all the time, I imagine. The support for double-char width cells in the terminals started to appear all the way back in the late seventies because Japan, you know, existed and kinda mattered.
14 comments
> The real fix requires agreement at the protocol level, across terminal emulators, shell applications, and TUI frameworks simultaneously.
Yeah, and ideally you want the backward compatibility, so we don't have to recompile the world or patch things like e.g. cat.
But yeah, the root of the problem is that a) the TUI-like application that manually drives the terminal, with cursor movement/line folding/redrawing etc. needs to know, at every single moment, the precise location of the cursor and the coordinates of every single character it outputted (to e.g. properly handle backspacing, including over the line folds: \b explicitly doesn't move to the previous line by default and very wide and old convention), and b) getting that coordination info from the terminal in quick, reliable, and side-effect free manner is impossible, so you have to guess.
It could just be the path to a Unix domain socket in an environment variable, where that socket speaks some kind of RPC protocol
If getting the current cursor position in the terminal were as easy (and as fast) as calling GetConsoleScreenBufferInfo, instead of sending "\e[6n" to the terminal and then reading input from it and looking for "\e[(\d+);(\d+)R" inside and then somehow unreading the input before that device report, yeah, that'd be nice and would allow solving a lot of problems with mere brute force. Sadly, it is not, and so most reimplementations of e.g. readline/linenoise functionality in shells and prompts (Erlang's shell went through 2 internal reimplementations just in my time using it, for example) are flying blind, hoping that their implementation of wcwidth(3) matches the terminal's one.
[0] https://learn.microsoft.com/en-us/windows/console/console-fu...
EDIT: Without saying that I think this is worthy and cool. I am just curious about the costs and benefits of such a tool.
> How often are complex scripts rendered in terminal?
If you speak the languages that use those scripts? Then all the time, I imagine. The support for double-char width cells in the terminals started to appear all the way back in the late seventies because Japan, you know, existed and kinda mattered.
- Everybody just uses english text, right?
- Ok, sometimes there might some weird accents or something
- Every character is about the same width
- Well, they're all integer numbers of characters wide
- No character is taller than an english I
- Everybody writes left to right
- Everyone writes horizontally
Also https://jeremyhussell.blogspot.com/2017/11/falsehoods-progra...
EDIT: How the hell do you format lists in HN comments
It can't handle terminal window resize and the layout gets messed up
I was surprised to see node based cli work much better with resize?
Anyone knows why?