crayon: Colored terminal output

Description

With crayon it is easy to add color to terminal output, create styles for notes, warnings, errors; and combine styles.

Usage

## Simple styles
red(...)
bold(...)
...
## See more styling below

Arguments

...

Strings to style.

Genaral styles

reset
bold
blurred (usually called ‘dim’, renamed to avoid name clash)
italic (not widely supported)
underline
inverse
hidden
strikethrough (not widely supported)

Text colors

black
red
green
yellow
blue
magenta
cyan
white
silver (usually called ‘gray’, renamed to avoid name clash)

Background colors

bgBlack
bgRed
bgGreen
bgYellow
bgBlue
bgMagenta
bgCyan
bgWhite

Styling

The styling functions take any number of character vectors as arguments, and they concatenate and style them:

  library(crayon)
  cat(blue("Hello", "world!\n"))

Crayon defines the %+% string concatenation operator, to make it easy to assemble stings with different styles.

  cat("... to highlight the " %+% red("search term") %+%
      " in a block of text\n")

Styles can be combined using the $ operator:

  cat(yellow$bgMagenta$bold('Hello world!\n'))

See also combine_styles. Styles can also be nested, and then inner style takes precedence:

  cat(green(
    'I am a green line ' %+%
    blue$underline$bold('with a blue substring') %+%
    ' that becomes green again!\n'
  ))

It is easy to define your own themes:

  error <- red $ bold
  warn <- magenta $ underline
  note <- cyan
  cat(error("Error: subscript out of bounds!\n"))
  cat(warn("Warning: shorter argument was recycled.\n"))
  cat(note("Note: no such directory.\n"))

Details

ANSI color support is automatically detected and used. Crayon was largely inspired by chalk https://github.com/sindresorhus/chalk.

Crayon defines several styles, that can be combined. Each style in the list has a corresponding function with the same name.

Examples

Run this code

cat(blue("Hello", "world!"))

cat("... to highlight the " \%+\% red("search term") \%+\%
    " in a block of text")

cat(yellow$bgMagenta$bold('Hello world!'))

cat(green(
 'I am a green line ' \%+\%
 blue$underline$bold('with a blue substring') \%+\%
 ' that becomes green again!'
))

error <- red $ bold
warn <- magenta $ underline
note <- cyan
cat(error("Error: subscript out of bounds!\n"))
cat(warn("Warning: shorter argument was recycled.\n"))
cat(note("Note: no such directory.\n"))

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