ansi-escape-sequences

  1. ansi-escape-sequences
    1. Description
    2. Author
    3. Requirements
    4. Procedures
      1. XTerm Enhanced Escape Sequences
    5. Examples
    6. License
    7. Version history
      1. Version 0.4
      2. Version 0.3
      3. Version 0.2
      4. Version 0.1

Description

Procedures to generate ANSI escape sequences.

Author

Mario Domenech Goulart. Erik Falor wrote the XTerm Enhanced Escape Sequences support.

Requirements

None

Procedures

[procedure] (cursor-position #!optional (line 0) (column 0))

Move the cursor to the specified position (coordinates). If a position is not specified, the cursor is moved to the home position at the upper-left corner of the screen (line 0, column 0).

[procedure] (cursor-up lines)

Move the cursor up by the specified number of lines without changing columns.

[procedure] (cursor-down lines)

Move the cursor down by the specified number of lines without changing columns.

[procedure] (cursor-forward columns)

Move the cursor forward by the specified number of columns without changing lines.

[procedure] (cursor-backward columns)

Move the cursor back by the specified number of columns without changing lines.

[procedure] (save-cursor-position)

Save the current cursor position. You can move the cursor to the saved cursor position by using the restore-cursor-position procedure.

[procedure] (restore-cursor-position)

Return the cursor to the position stored by the save-cursor-position.

[procedure] (hide-cursor)

Hide the cursor.

[procedure] (show-cursor)

Show the cursor.

[procedure] (erase-display)

Clear the screen and move the cursor to the home position (line 0, column 0).

[procedure] (erase-line)

Clear all characters from the cursor position to the end of the line (including the character at the cursor position).

[procedure] (set-mode attrib)

Change the screen width or type to the mode specified by one of the following values (symbols):

[procedure] (reset-mode attrib)

Reset the mode by using the same values as set-mode.

[procedure] (set-text attribs text #!optional (reset #t))

Change the colors and attributes of text (such as bold and underline) displayed on the screen. The following attributes are available (symbols):

bg- is for background. fg- is for foreground.

XTerm Enhanced Escape Sequences

The following procedures emit escape sequences first introduced by XTerm, but which have since been adopted by other terminals.

[procedure] (set-text256 attribs text #!optional (reset #t))

Change the colors and attributes of text (such as bold and underline) displayed on the screen. The following attributes are available, the same as set-text (symbols):

Colors are specified with a two-element list, the first element being one of the symbols foreground or background followed by a number in the range 0..255. Most terminals use the same color palette by default: colors 0-15 are the familiar 16 terminal colors. Colors 17-232 form a 6x6x6 color cube, with the remaining 24 colors defining a grayscale ramp from dark to light.

[procedure] (set-color256! index red green blue)

Redefine the RGB value of color index. The values red, green, blue are integers in the range 0..255. Be aware that some terminals which will output 256 colors won't necessarily honor this escape sequence.

This egg's source is distributed with a CHICKEN port of the 256colors2.pl program used to test a terminal's ability to display colors beyond the standard 16.

[procedure] (set-title text)

Sets the terminal's window title to text.

Examples

Here's a video (on YouTube) by Erik Falor showing an example of what you can do with the XTerm Enhanced Escape Sequences: https://www.youtube.com/watch?v=gTqHlKwziNU. The code for this example can be found here: http://paste.lisp.org/display/144140.

And here is a video showing the execution of the program below: OGV (Theora), AVI

(use posix ansi-escape-sequences)

(set-buffering-mode! (current-output-port) #:none)

(display (save-cursor-position))
(for-each (lambda (letter)
            (display letter)
            (sleep 1)
            (cursor-forward 1))
          '("c" "h" "i" "c" "k" "e" "n"))

(display " ")
(for-each (lambda (letter)
            (display (set-text '(bg-black fg-yellow) letter))
            (sleep 1)
            (cursor-forward 1))
          '("r" "o" "c" "k" "s" "!"))

(display (restore-cursor-position))
(display (erase-line))

(for-each (lambda (letter)
            (display letter)
            (sleep 1)
            (cursor-forward 1))
          '("c" "h" "i" "c" "k" "e" "n"))

(display " ")
(for-each (lambda (letter)
            (display (set-text '(bg-red fg-white) letter))
            (sleep 1)
            (cursor-forward 1))
          '("r" "u" "l" "e" "s" "!"))

(print "")

License

BSD

Version history

Version 0.4

Version 0.3

Version 0.2

Fixed escape sequences with more than one argument (reported by Felix)

Version 0.1

Initial release