Guides/Boxdraw
Box Draw Characters
J uses box drawing characters when displaying boxed data. Typically this requires a fixed pitch font.
The most portable way of drawing boxes is with the ascii characters +|- as below:
+---+---+----+ |abc|def|ghij| +---+---+----| |2 |3 |4 | +---+---+----+
This displays predictably in all environments, works in plain text email, and is the most portable form for communicating between users. When these aren't important and you have a suitable font you can use special box draw chars to provide crisper displays.
Box drawing with unicode J font characters is as below:
┌───┬───┬────┐ │abc│def│ghij│ ├───┼───┼────┤ │2 │3 │4 │ └───┴───┴────┘
J draws boxes with 11 characters:
upper left corner T down upper right corner T right cross T left lower left corner T up lower right corner vertical horizontal
The values for the 11 characters can be queried with 9!:6 and set with 9!:7:
Box draw with J font chars is set with:
9!:7 [ (16+i.11){a.
Box draw with +|- is set with:
9!:7 '+++++++++|-'
Equivalently, call the utility boxdraw_j_:
boxdraw_j_ 0 NB. J font chars boxdraw_j_ 1 NB. ascii font chars
The default boxdraw is set in the configuration files: base.cfg (jconsole and JHS) and qtide.cfg (Qt IDE).
Note that box draw can also use UTF-8 characters, e.g.
9!:7 [ 218 194 191 195 197 180 192 193 217 179 196{a.
J Engine input/output is in UTF-8 and the 9!:7 J font setting results in the Unicode values:
9484 9516 9488 9500 9532 9508 9492 9524 9496 9474 9472
Note: some unicode fixed pitch fonts do not have box draw characters of the same pitch and do not display well.