Ecma-48 proposed styling controls update updated & math expression representation proposal update

[Giacomo Catenazzi]

CSI is defined in Unicode and in other ECMA standards: it is the 
terminal command usually send as `ESC [` (and if should be terminated by 
characters between 0x40 and 0x7E, but there were bugs and exceptions on 
some platforms), there is also one single character in C1 (so still two 
bytes in UTF-8), but many terminal disregard this alternate (which it is 
also very old).

But so we see the advantage of having elements (and tags) written as 
clear text (as in HTML, LaTeX, etc.): if we do not understand one 
element we can google it. With ECMA-48 code: either is standard, or good 
luck to find some references.

ECMA-48-like syntax is bad, difficult to enhance without requiring 
updates on all programs (contrary to HTML: tags can be just ignored, 
without consequences to next ones, or previous *non-closed* one). Note: 
this fact is caused by a different reason, which modern mark-up 
languages shares: they are *structured* (which ECMA-48 is not, not TeX, 
but TeX is frozen). Past gives us a lesson, let's learn about it, and 
not doing the same errors. ECMA-48 is the past (still used on some 
appliances, but without expectation to enhance it too much: we have 
alternate graphical interfaces).

[Note: but I think there is a need for an update of ECMA-48: to 
standardise common behaviour, but it should be done by the maintainers 
of the different terminals].

cate



On 8 Jan 2024 13:19, William_J_G Overington via Unicode wrote:
> Previously I wrote:
> 
> 
>  > MORE NEEDED about Anne showing Patricia how to code the text in green 
> and yellow.
> 
> 
> I managed to download the PDF document to local storage and I have found 
> on page 55 of the PDF document a table with codes in Kent's proposed 
> enhanced system for setting the colours to alphanumerics green and 
> alphanumerics yellow so that writing of the story can make progress.
> 
> 
> It appears that for alphanumerics green SP? CSI 92m is needed and that 
> for alphanumerics yellow that SP? CSI 93m is needed. I expect that the 
> code alphanumerics green will be needed at the start of the line and 
> after the name Gutenberg and that alphanumerics yellow will be needed 
> before the name Gutenberg. A teletext alphanumerics colour code 
> automatically generates a space in the display, so I am wondering if, 
> for the possibility of making round-trip conversion back to teletext 
> format that the space should be after the code rather than before it as 
> is listed in Kent's document so that in a round trip the space following 
> the colour code can be omitted when it is reached rather than needing to 
> go back and remove it when the colour code is detected.
> 
> 
> I do not currently know what CSI means in this context. There are 808 
> mentions of CSI is the PDF document and the first one is on page 6 but 
> at present I do not understand it.
> 
> 
> I am thinking that if this story can be completed and includes a 
> reference to Kent's document and Anne and Patricia have a discussion 
> about why Anne thinks it better to have the space after the colour code 
> rather than before then the story might well be a good learning resource.
> 
> William
> 
>