A small program to make using 256 colors in Nim less painful.

colors.nim

import strformat

# A small program to make using 256 colors in Nim less painful.
# Original ZSH version from:
# P.C. Shyamshankar <[email protected]>
# Copied from https://github.com/sykora/etc/blob/master/zsh/functions/spectrum/
#
# Nim rewrite by Laszlo Szathmary <[email protected]>
# thanks to narimiran and kickeroo for making the code more idiomatic Nim code
#
# 16 Terminal Colors
# -- ---------------
#  0 black
#  1 red
#  2 green
#  3 yellow
#  4 blue
#  5 magenta
#  6 cyan
#  7 white
#  8 bright black
#  9 bright red
# 10 bright green
# 11 bright yellow
# 12 bright blue
# 13 bright magenta
# 14 bright cyan
# 15 bright white

type
  FX = enum
    fxReset = "\x1b[0m"
    fxBold = "\x1b[1m"
    fxNoBold = "\x1b[22m"
    fxItalic = "\x1b[3m"
    fxNoItalic = "\x1b[23m"
    fxUnderline = "\x1b[4m"
    fxNoUnderline = "\x1b[24m"
    fxBlink = "\x1b[5m"
    fxNoBlink = "\x1b[25m"
    fxReverse = "\x1b[7m"
    fxNoReverse = "\x1b[27m"

const
  reset_color = fxReset

  FG = block:
    var res: array[256, string]
    for color in 0 .. 255:
      res[color] = &"\x1b[38;5;{color}m"
    res

  BG = block:
    var res: array[256, string]
    for color in 0 .. 255:
      res[color] = &"\x1b[48;5;{color}m"
    res

  TEXT = "Arma virumque cano Troiae qui primus ab oris"
# const

# Show all 256 colors with color number
proc spectrum_ls() =
  for code in 0 .. 255:
    echo &"{code}: {FG[code]}{TEXT}{reset_color}"

# Show all 256 colors where the background is set to specific color
proc spectrum_bls() =
  for code in 0 .. 255:
    echo &"{code}: {BG[code]}{TEXT}{reset_color}"

proc main() =
  spectrum_ls()
  spectrum_bls()

  let text = "the Nim programming language"

  echo &"{FG[153]}{text}{reset_color}"
  echo &"{fxBold}{FG[153]}{text}{reset_color}"
  echo &"{fxItalic}{FG[153]}{text}{reset_color}"
  echo &"{fxUnderline}{FG[153]}{text}{reset_color}"
  echo &"{fxBlink}{FG[153]}{text}{reset_color}"
  echo &"{fxReverse}{FG[153]}{text}{reset_color}"

# ############################################################################

when isMainModule:
  main()

• Screenshot: https://i.imgur.com/C1SSZF0.png
• Blog post: https://ubuntuincident.wordpress.com/2018/11/25/nim-using-the-xterm-256-colors-in-the-terminal/