Term::Chrome - DSL for colors and other terminal chrome
use Term::Chrome qw<Red Blue Bold Reset Underline Green color>; # Base color constant and attribute say Red, 'red text', Reset; # Composition, using operator overloading say Red/Blue+Bold, 'red on blue', Reset; # Undo say Bold, 'bold', !Bold, 'not bold'; # Extended xterm-256 colors say color(125) + Underline, 'Purple', Reset; # Define your own constants use constant Pink => color 213; # Use ${} around Chrome expression inside strings say "normal ${ Red+Bold } RED ${ +Reset } normal"; # Extract components say( (Red/Blue)->bg, "blue text", (Green+Reset)->flags );
Chromizer: get a closure that applies given chrome before, and undo after the argument.
# Get an efficient chromizer my $boldifier = \&{ +Bold }; # Use the chromizer say $boldifier->("bold text"); # Same as: say Bold, "bold text", !Bold; # Short lived chromizers using color literals: say(&{+Red}('red')); say(&{ Red/Blue + Bold }('red on blue')); # Same, but requires perl 5.21.4+ #say(( Red/Blue + Bold )->('red on blue'));
Term::Chrome is a domain-specific language (DSL) for terminal decoration (colors and other attributes).
Term::Chrome
In the current implementation stringification to ANSI sequences for xterm and xterm-256 is hard-coded (which means it doesn't use the terminfo(5) database), but this gives optimized (short) strings.
xterm
xterm-256
Colors and attributes are exposed as objects that have overloading for arithmetic operators.
color(0-255)
Build a Term::Chrome object with the given color number. You can use this constructor to create your own set of color constants.
For example, color(0) gives the same result as Black (but not the same object).
color(0)
Black
Each of these function return a Chrome object.
Black: color 0
color 0
Red: color 1
Red
color 1
Green: color 2
Green
color 2
Yellow: color 3
Yellow
color 3
Blue: color 4
Blue
color 4
Magenta: color 5
Magenta
color 5
Cyan: color 6
Cyan
color 6
White: color 7
White
color 7
The exact rendering of each flag is dependent on how the terminal implements them. For example Underline and Blink may do nothing.
Underline
Blink
Bold
Reverse
Reset: reset all colors and flags
Reset
ResetFlags: reset (undo) all chrome flags (Bold, Underline, Blink, Reverse)
ResetFlags
ResetFg: reset (undo) foreground color
ResetFg
ResetBg: reset (undo) background color
ResetBg
Here are the methods on Term::Chrome objects:
fg
Extract the Chrome object of just the foreground color. Maybe undef.
undef
bg
Extract the Chrome object of the just background color. Maybe undef.
flags
Extract a Chrome object of just the decoration flags. Maybe undef.
/
Combine a foreground color (on the left) with a background color.
Example:
my $red_on_black = Red / Black;
+
Add decoration flags (on the right) to colors (on the left).
my $bold_red = Red + Bold;
!
Returns a chrome which is the reverse of chrome to which negation is applied.
my $reset_foreground = ! Red; my $reset_colors = ! (Red / Black);
The reverse of Reset, ResetFg, ResetBg, ResetFlags is nothing.
""
Transform the object into a string of ANSI sequences. This is particularly useful to directly use a Chrome object in a double quoted string.
${}
Same result as "" (stringification). This operator is overloaded because it is convenient to interpolate Chrome expressions in double-quoted strings.
Examples:
say "normal ${ +Red } red ${ +Reset }"; say "normal ${ Red + Bold } red ${ +Reset }";
Note that you must force expression parsing context when a Chrome constant is used alone inside ${ }: ${ +Red } or ${ (Red) } or ${ Red() }. use strict 'vars'; will detect those cases, but you may miss them in one-liners.
${ }
${ +Red }
${ (Red) }
${ Red() }
use strict 'vars';
&{}
Wrap some text with the given chrome and Reset.
say Red->("red text"); # Same result as: say Red, "red text", Reset;
Unfortunately perl had a bug (perl RT#122607) that makes this feature not much usable in practice when applied to constants. That bug is fixed in perl 5.21.4+. On perl < 5.21.4 you have to wrap the chrome constant in a do {} or use &{}():
do {}
&{}()
say do{ Red }->("red text"); say &{ +Red }("red text");
Codulation can also be used to extract a colorizer sub that will be more efficient if you use it multiple times:
my $redifier = \&{ Red }; say $redifier->("red text");
See the warnings about ${} and &{} above.
ISO 6429 / ECMA 48: https://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf (reference for SGR is at page 61, numbered 75 in PDF)
XTerm Control Sequences: http://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Functions-using-CSI-_-ordered-by-the-final-character_s_
Comments on each modules are opinions of the author.
Term::ANSIColor: the same basic features (and the others should not be in Term::ANSIColor itself but in an extension), but with an awful API I could never even consider to use while keeping my sanity.
Term::ScreenColor
PerlIO::via::ANSIColor
AngelPS1 or https://github.com/dolmen/angel-PS1: "The Angel's Prompt" is the project for which Term::Chrome has been built. AngelPS1::Compiler, the angel-PS1 compiler has special support for Term::Chrome values.
angel-PS1
Did you know that chartreuse is one of the favorite colors of Larry Wall?
Olivier Mengué <dolmen@cpan.org>
Copyright © 2013-2018 Olivier Mengué.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl 5 itself.
To install Term::Chrome, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Term::Chrome
CPAN shell
perl -MCPAN -e shell install Term::Chrome
For more information on module installation, please visit the detailed CPAN module installation guide.