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package chalk
import "fmt"
// Color represents one of the ANSI color escape codes.
type Color struct {
value int
// Value returns the individual value for this color
// (Actually it's really just its index in the list
// of color escape codes with the list being
// [black, red, green, yellow, blue, magenta, cyan, white].
func (c Color) Value() int {
return c.value
// Color colors the foreground of the given string
// (whatever the previous background color was, it is
// left alone).
func (c Color) Color(val string) string {
return fmt.Sprintf("%s%s%s", c, val, ResetColor)
func (c Color) String() string {
return fmt.Sprintf("\u001b[%dm", 30+c.value)
// NewStyle creates a style with a foreground of the
// color we're creating the style from.
func (c Color) NewStyle() Style {
return &style{foreground: c}
type textStyleDemarcation int
func (t textStyleDemarcation) String() string {
return fmt.Sprintf("\u001b[%dm", t)
// A TextStyle represents the ways we can style the text:
// bold, dim, italic, underline, inverse, hidden or strikethrough.
type TextStyle struct {
start, stop textStyleDemarcation
// TextStyle styles the given string using the desired text style.
func (t TextStyle) TextStyle(val string) string {
if t == emptyTextStyle {
return val
return fmt.Sprintf("%s%s%s", t.start, val, t.stop)
// NOTE: this function specifically does not work as desired because
// text styles must be wrapped around the text they are meant to style.
// As such, use TextStyle() or Style.Style() instead.
func (t TextStyle) String() string {
return fmt.Sprintf("%s%s", t.start, t.stop)
// NewStyle creates a style starting with the current TextStyle
// as its text style.
func (t TextStyle) NewStyle() Style {
return &style{textStyle: t}
// A Style is how we want our text to look in the console.
// Consequently, we can set the foreground and background
// to specific colors, we can style specific strings and
// can also use this style in a builder pattern should we
// wish (these will be more useful once styles such as
// italics are supported).
type Style interface {
// Foreground sets the foreground of the style to the specific color.
// Background sets the background of the style to the specific color.
// Style styles the given string with the current style.
Style(string) string
// WithBackground allows us to set the background in a builder
// pattern style.
WithBackground(Color) Style
// WithForeground allows us to set the foreground in a builder
// pattern style.
WithForeground(Color) Style
// WithStyle allows us to set the text style in a builder pattern
// style.
WithTextStyle(TextStyle) Style
String() string
type style struct {
foreground Color
background Color
textStyle TextStyle
func (s *style) WithBackground(col Color) Style {
return s
func (s *style) WithForeground(col Color) Style {
return s
func (s *style) String() string {
var toReturn string
toReturn = fmt.Sprintf("\u001b[%dm", 40+s.background.Value())
return toReturn + fmt.Sprintf("\u001b[%dm", 30+s.foreground.Value())
func (s *style) Style(val string) string {
return fmt.Sprintf("%s%s%s", s, s.textStyle.TextStyle(val), Reset)
func (s *style) Foreground(col Color) {
s.foreground = col
func (s *style) Background(col Color) {
s.background = col
func (s *style) WithTextStyle(textStyle TextStyle) Style {
s.textStyle = textStyle
return s
var (
// Colors
Black = Color{0}
Red = Color{1}
Green = Color{2}
Yellow = Color{3}
Blue = Color{4}
Magenta = Color{5}
Cyan = Color{6}
White = Color{7}
ResetColor = Color{9}
// Text Styles
Bold = TextStyle{1, 22}
Dim = TextStyle{2, 22}
Italic = TextStyle{3, 23}
Underline = TextStyle{4, 24}
Inverse = TextStyle{7, 27}
Hidden = TextStyle{8, 28}
Strikethrough = TextStyle{9, 29}
Reset = &style{
foreground: ResetColor,
background: ResetColor,
emptyTextStyle = TextStyle{}
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