Comment 46 for bug 263822

Usama,

The reason for bug #1537064 is me nagging Yaron. The problem of BiDi cannot be solved in a terminal vt100 environment. The reason - is that the application does not telling the VTE the boundaries of the paragraph.

Imagine "mc" opeenning a dialog to rename a file. Lets check the options;

1) A line contains RTL - apply BiDi to it and display line in RTL. Funny things will happen, as the line bellow will also be reverted. The file name of the right panel - will be on the left.
2) Even funnier - when you type lam and aliph - those will be displayed as a single glyph on screen and the app counted two unicode chars (4 bytes in UTF8) and now the left margin is off by one (the frames of the dialog are also text, remember - the app needs to pad spaces until the "|" char will be displayed).
3) OK - instead of reverting a whole line - lets revers each word - this is broken since you now have proper words in LTR order (lets ignore #2)
4) OK - lets detect the word boundary and de-order "n" words - when happens when the first word of the next paragraph starts with an english word? the direction will be broken.

I assume we can find other problems. Lets find solutions:
1) Do the BiDi in apps, while assuming the ternimal is dumb: OK, it will work on xterm, konsole, gnome-terminal, and VT. Problem - we need to fix *ALL* terminal apps.
2) Do the BiDi in terminals - in order to fix all above problems, we need a way to report to the terminal about the regions that will contain text that he may modify. Then code a reference implementation, issue an RFC and port to all other terminals.

TL.DR. Ternimals are broken by design and cannot support RTL/BIDI. Just move on and use X11/Wayland for Arabic/Farsi/Hebrew/Whatever and don't translate those interfaces to the native languages on terminals.