From: Jim Allan (jallan@smrtytrek.com)
Date: Thu Sep 04 2003 - 11:58:43 EDT
Kent Karlson wrote:
> Jim Allan wrote:
> ...
>> One may note the common use of the greater-than and less-than signs as
>
>> angle brackets in many publications
>
> Just because < and > are in ASCII, the have been used as approximations.
That was the origin of this practice.
However the practice is found now in professional technical publishing
as a matter of choice, for example in modern linguistics and in
Backus-Naur notation where the more normal angle brackets are certainly
available for use.
>> including the Unicode standard. I
>> don't think that necessitates coding separate characters.
>
> Yes, it does:
> 27E8;MATHEMATICAL LEFT ANGLE BRACKET;Ps;0;ON;;;;;Y;;;;;
> 27E9;MATHEMATICAL RIGHT ANGLE BRACKET;Pe;0;ON;;;;;Y;;;;;
>
> (Despite the name, you can use them outside of math expressions.)
>
> You also have the (mathematical):
> 2991;LEFT ANGLE BRACKET WITH DOT;Ps;0;ON;;;;;Y;;;;;
> 2992;RIGHT ANGLE BRACKET WITH DOT;Pe;0;ON;;;;;Y;;;;;
>
> But:
> 3008;LEFT ANGLE BRACKET;Ps;0;ON;;;;;Y;OPENING ANGLE BRACKET;;;;
> 3009;RIGHT ANGLE BRACKET;Pe;0;ON;;;;;Y;CLOSING ANGLE BRACKET;;;;
> are for CJK use.
I am quite aware that these are encoded. Angle brackets are also to be
found in the well known and widely available Adobe symbol character set
employed in various Symbol fonts and I have used them.
But the GREATER-THAN and LESS-THAN signs sometimes continue to be used
*by preference* for angle brackets even when angle bracket glyphs are
available.
For an example, from
http://www.unicode.org/versions/Unicode4.0.0/Preface.pdf under *Sequences*:
<< A sequence of two or more code points may be represented by a
comma-delimited list, set off by angle brackets. For this purpose angle
brackets consist of U+003C LESS-THAN-SIGN and U+003E GREATER-THAN-SIGN.
Spaces are optional after the comma, and U+ notation for the code point
is also optional—for example, “<U+0061, U+0300>”. >>
The common *deliberate* use of LESS-THAN and GREATER-THAN for angle
brackets does not require that clones be encoded in Unicode for that use.
Similarly the convention that I and some others use of sometimes
indicating quoted text in email or on forums by "<<" and ">>" does not
require any new encoding symbols in Unicode.
Symbol characers often have multiple and inconsistant usage without
ceasing to be the same characters.
Jim Allan
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