Context-specific markup brackets (from Re: Why 17 planes?)

On Thursday 29 November 2012, Doug Ewell <doug_at_ewellic.org> wrote a detailed reply to a post that I had made.
 
I thought about what Doug wrote and am now putting forward an idea that could possibly be useful in various contexts.
 
Would it be a good idea to define a new block of characters within Unicode/10646 such that characters would be encoded in pairs, possibly with visible glyphs as context-specific markup brackets?
 
For example, the block could be named as Context-specific markup brackets.
 
For example, there could be the following.
 
HIEROGLYPHIC MARKUP START
HIEROGLYPHIC MARKUP END
SIGNWRITING MARKUP START
SIGNWRITING MARKUP END
 
and other pairs for various systems when encoded.
 
I am thinking that this would mean that where some applications use a combination of Unicode/10646 characters, (sometimes including specific circumstances characters such as Hieroglyphics characters) and markup, that the fact that some of the stream of characters are used in a markup context and some are not would be detectable from within the character stream, in both forward and backward parsing, instead of being designated in a possibly non-interoperably-notifiable manner from outside of the character stream.
 
This would mean that a stream of characters received could be regarded as plain text until a context-specific markup bracket were detected.
 
The reason for visible glyphs for the context-specific markup brackets would be as a fail-safe feature so that a plain text displaying system that did not detect markup of the specific type would clearly display a glyph as an indication that markup is present.
 
The reasoning that lead me to this suggestion follows from the following text that Doug wrote, as well as being aware of various other threads about situations where markup could be involved.
 
> Just create a markup language with normal characters, and have your "specially adapted email reading system" interpret the markup sequences and convert them to normal text:
>
> [+10+]
> [+200+]
> Margaret Gattenford
> ...
>
 
I realized that for most uses my research does not need displayed symbol glyphs as the codes would be localized into text: for those situations where a glyph display would be useful or interesting, glyph substitution with an OpenType font or some other advanced font format font could be used.
 
Yet using [+ and +] as markup brackets concerns me as that is then using ordinary Unicode/10646 characters out of their defined meanings without any prior notification from within the text stream that that is the situation.
 
This lead to the suggestion earlier in this post.
 
Is this an idea that could be of usefulness?
 
William Overington
 
1 December 2012
 
Received on Sat Dec 01 2012 - 07:06:53 CST