ansi_term.pl -- Print decorated text to ANSI consoles

This library allows for exploiting the color and attribute facilities of most modern terminals using ANSI escape sequences. This library provides the following:

• ansi_format/3 allows writing messages to the terminal with ansi attributes.
• It defines the hook prolog:message_line_element/2, which provides ansi attributes for print_message/2.

See also

- http://en.wikipedia.org/wiki/ANSI_escape_code

 ansi_format(+Attributes, +Format, +Args) is det

Format text with ANSI attributes. This predicate behaves as format/2 using Format and Args, but if the current_output is a terminal, it adds ANSI escape sequences according to Attributes. For example, to print a text in bold cyan, do

?- ansi_format([bold,fg(cyan)], 'Hello ~w', [world]).

Attributes is either a single attribute or a list thereof. The attribute names are derived from the ANSI specification. See the source for sgr_code/2 for details. Some commonly used attributes are:

• bold
• underline
• fg(Color), bg(Color), hfg(Color), hbg(Color)

Defined color constants are below. default can be used to access the default color of the terminal.

• black, red, green, yellow, blue, magenta, cyan, white

ANSI sequences are sent if and only if

• The current_output has the property tty(true) (see stream_property/2).
• The Prolog flag color_term is true.

 sgr_code(+Name, -Code)[private]

True when code is the Select Graphic Rendition code for Name. The defined names are given below. Note that most terminals only implement this partially.

reset	all attributes off
bold
faint
italic
underline
blink(slow)
blink(rapid)
negative
conceal
crossed_out
font(primary)
font(N)	Alternate font (1..8)
fraktur
underline(double)
intensity(normal)
fg(Name)	Color name
bg(Name)	Color name
framed
encircled
overlined
ideogram(underline)
right_side_line
ideogram(underline(double))
right_side_line(double)
ideogram(overlined)
left_side_line
ideogram(stress_marking)
-Off	Switch attributes off
hfg(Name)	Color name
hbg(Name)	Color name

See also

- http://en.wikipedia.org/wiki/ANSI_escape_code

 prolog:message_line_element(+Stream, +Term) is semidet[multifile]

Hook implementation that deals with ansi(+Attr, +Fmt, +Args) in message specifications.