ansi.el

This package defines functions that turns simple strings to ansi strings. Turning a string into an ansi string can be to add color to a text, add color in the background of a text or adding a style, such as bold, underscore or italic.

Installation

Add ansi to your Cask file:

(depends-on "ansi")

Usage

All colors, background colors and styles can be accessed via a function with the ansi- prefix. For example:

;; Color text
(ansi-red "foo")
(ansi-blue "bar")

;; Color background
(ansi-on-red "foo")
(ansi-on-blue "bar")

;; Add style
(ansi-bold "foo")
(ansi-blink "bar")

It can become quite cumbersome to use those function names if the coloring is a little bit more advanced. To simplify this, there's a DSL, which makes this much more pleasant. If within a with-ansi block, the ansi- prefix is not necessary anymore. This is the same as the above.

;; Color text
(with-ansi
 (red "foo")
 (blue "bar"))

;; Color background
(with-ansi
 (on-red "foo")
 (on-blue "bar"))

;; Add style
(with-ansi
 (bold "foo")
 (blink "bar"))

You can also use ansi-apply if you only have the name of the color:

(ansi-apply 'red "foo %s" "bar")

CSI

Ansi supports CSI codes, for example moving the cursor:

(ansi-up)
(ansi-down 3)
(ansi-csi-apply 'forward)
(ansi-csi-apply "J" 10)

Nesting

Lets say you want to make a text bold, red and blinking. You can do this with nesting.

;; Without DSL
(ansi-bold
 (ansi-red (ansi-blink "foo bar")))

;; Using DSL
(with-ansi
 (bold (red (blink "foo bar"))))

Inhibit ANSI and CSI sequences

If you are on a dumb terminal, not running on tty or you just want to disable colors, you can inhibit all special/control sequences by setting ansi-inhibit-ansi to t. Text will still be formated and output, but without the special/control sequences.

If you are running your Emacs code from shell, for example as a wrapper for a binary for your package, you can detect whether you are running in a tty with this code:

INHIBIT_ANSI="t"
if [ -t 1 ] ; then
    INHIBIT_ANSI="nil"
fi

## here you run your script
exec emacs --batch --no-init-file --no-site-file --no-splash \
     --eval "(ansi-inhibit-ansi $INHIBIT_ANSI)" \  ## << disable ansi if not tty
     --load=elsa --funcall=elsa-run  ## load your package and run your fn