According to:
http://www.alanwood.net/unicode/combining_diacritical_marks_for_symbols.html
the arrow combining characters are:
4 u: 16b20d4 + 0 1 2 3 13 22 26 27
⃪⃮⃯⃔⃕⃖⃗⃡
However, according to:
http://unicode.org/faq/char_combmark.html#12b
You need a font with specific support for a particular combined glyph in order
to see it. I don't understand why displays couldn't simply overlay the two
primitive glyphs if the font lacks a specific combined glyph (similar to how
they can italicize or bold or small-caps fonts that don't contain specific
support for those typefaces), but that's just my ignorance.
Anyway, I downloaded the two "broad spectrum" fonts that link recommends
(Doulos and Charis), and using either, when I issue:
'A',.4 u: 16b20d4 + 0 1 2 3 13 22 26 27
I can see A properly composed with the latter two "COMBINING LEFT/RIGHT ARROW
BELOW", but the other combinations result in A followed by an empty rectangle,
which is symptomatic of lacking font support, according to the Unicode FAQ link.
So there's no quick answer. You need a Unicode font that supports these
overstrikes, in addition to all the other requirements of a J font (for
example, fixed-width, or making "control characters" visible, etc). That is,
assuming you are simply displaying these combined characters in the J session
manager. If you're e.g. writing them to a file or email, etc, you have more
degrees of freedom (and error, of course -- you may have to instruct your
clients to download and install a specific font).
-Dan
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Brian Schott
Sent: Monday, March 08, 2010 1:52 PM
To: programm...@jsoftware
Subject: [Jprogramming] unicode overstrike
At the link below there is a statement, describing
how U+0061 and U+0332 together can be used to create the APL
symbol `a underbar` because U+0332 has the combining
characteristic which enables overstrikes in unicode.
http://unicode.org/book/ch12.pdf
I want to overstrike alphabetic characters with
directional arrows such as the following ones, but cannot
see how to give these characters the combining
characteristic oversstriking would require. Is that
possible; I cannot find any existing combining characters
that suggest any directionality.
16b2190
16b2191
16b2192
16b2193
16b2196
16b2197
16b2198
16b2199
4 u: 16b2190 + i. 10 NB. try this in J to see the arrows
--
(B=)
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