> Date: Sun, 03 Feb 2019 18:10:15 +0200 > Cc: [email protected], [email protected] > From: Eli Zaretskii via Unicode <[email protected]> > > I think there are hard problems even for such "simple" utilities, and > I will start a separate thread about this.
I think we spent enough time discussing issues of complex script shaping in terminal emulators, something that IMO took us too far aside. The basic problems with bidi reordering of text-mode output start much sooner, and are much more fundamental. I think they should be considered first. The document cited at the beginning of the parent thread states that "simple" text-mode utilities, such as 'echo', 'cat', 'ls' etc. should use the "implicit" mode of bidi reordering, with automatic guessing of the base paragraph direction. I think this already present non-trivial problems. The fundamental problem here is that most "simple" utilities use hard newlines to present text in some visually plausible format. Even when these utilities just emit text read from files (as opposed to generating the text from the program), you will normally see each line end with a hard newline, because the absolute majority of text files have a hard newline and the end of each line. When bidirectional text is reordered by the terminal emulator, these hard newlines will make each line be a separate paragraph. And this is a problem, because the result will be completely random, depending on the first strong directional character in each line, and will be visually very unpleasant. Just take the output produced by any utility when invoked with, say, the --help option, and try imagining how this will look when translated into a language that uses RTL script. So I think determination of the paragraph direction even in this simplest case cannot be left to the UBA defaults, and there's a need to use "higher-level" protocols for paragraph direction. IOW, the implicit mode described in the above-mentioned document needs to be augmented by a smarter method of determining the base paragraph direction. (I might have a suggestion for that, if people agree with the above reasoning.)
