proposal (9.5) : psql unicode border line styles

Hello

I am returning back to this topic. Last time I proposed styles:

http://www.postgresql.org/message-id/CAFj8pRCLgoKtrYjPbToncpgyfTRcZ-ZgfOwdc1jquLB+eDe0Tw@mail.gmail.com

http://postgres.cz/wiki/Pretty_borders_in_psql

This experiment fails, but there are some interesting tips in discuss.

So I propose little bit different proposal - choose one predefined style
for any table lines elements. These styles are active only when "linestyle"
is unicode.

So possible line elements are:

* border,
* header_separator,
* row_separator,
* column_separator,

Possible styles (for each element)

* none,
* single,
* double,
* thick,

It should to have enough variability to define all styles proposed early. I
hope, so this proposal is secure and simple for usage. Styles should be
persistently saved in .psqlrc file - and some examples can be in
documentation.

Usage:

\pset linestyle_border double
\pset linestyle_header_separator single
\pset linestyle_row_separator single
\pset linestyle_column_separator single

\pset linestyle unicode

╔═══╤════════════╤═══════╗
║ a │ b │ c ║
╟───┼────────────┼───────╢
║ 1 │ 2012-05-24 │ Hello ║
╟───┼────────────┼───────╢
║ 2 │ 2012-05-25 │ Hello ║
║ │ │ World ║
╚═══╧════════════╧═══════╝
(2 rows)

Comments, ideas ?

Regards

Pavel