style.go

package style

// CurrentStyler is the current selected Styler. Default to a style.NewTerm()
var CurrentStyler Styler = NewTerm()

// Styler represents any type that knows how to format texts.
type Styler interface {
	// Upper changes a string case to upper case
	Upper(string) string

	// Lower changes a string case to lower case
	Lower(string) string

	// TitleCase changes all letters that begin words to their title case.
	TitleCase(string) string

	// Black changes a string foreground color to black
	Black(string) string

	// Red changes a string foreground color to red
	Red(string) string

	// Green changes a string foreground color to green
	Green(string) string

	// Yellow changes a string foreground color to yellow
	Yellow(string) string

	// Blue changes a string foreground color to blue
	Blue(string) string

	// Magenta changes a string foreground color to magenta
	Magenta(string) string

	// Cyan changes a string foreground color to cyan
	Cyan(string) string

	// White changes a string foreground color to white
	White(string) string

	// Inverse changes a string by inverting its fore- and back-ground
	// colors
	Inverse(string) string

	// Bold changes a string case to bold
	Bold(string) string

	// Italic changes a string case to italic
	Italic(string) string

	// Underline changes a string to be underlined
	Underline(string) string

	// Crossout changes a string to be strikethrough
	Crossout(string) string

	// Tab increases the tabulation level (indents then wraps the provided text)
	Tab() func(string) string

	// Header returns text as a chapter's header.
	Header(int) func(string) string

	// Metadata returns formatted metadata information.
	// Usual metadata are "title", "authors", "date", "mansection".
	Metadata(map[string]string) string

	// Paragraph returns text as a new paragraph.
	Paragraph(string) string

	// BulletedList returns a new bulleted-list (each list item has a leading
	// bullet).
	BulletedList() func(...string) string

	// OrderedList returns a new ordered-list (each list item has a leading
	// auto-incrementing enumerator).
	OrderedList() func(...string) string

	// Define returns a term definition.
	Define(string, string) string

	// Table draws a table.
	Table(...[]string) string

	// Link returns links to internal or external resources
	Link(string, string) string

	// Img returns links to an image
	Img(string, string) string

	// Escape escapes the provided text.
	// Chaining Escapes with Styler formatting functions can lead to unexpected results.
	Escape(string) string
}

// Chain combines several styling functions into one. Styling functions are
// executed in the provided order.
//
// Notice that chaining styling functions can be tricky, and should be used
// wisely (for example, some styling functions can alter formatting tags
// inserted by the previous chaining function voiding the result).
func Chain(fn ...func(string) string) func(string) string {
	return func(src string) string {
		s := src
		for _, f := range fn {
			s = f(s)
		}
		return s
	}
}

// FuncMap returns a ready to use text/template.FuncMap to extend available
// template mapping by exposing some st styling functions.
func FuncMap(st Styler) map[string]interface{} {
	return map[string]interface{}{
		"upper":     st.Upper,
		"lower":     st.Lower,
		"titlecase": st.TitleCase,
		"black":     st.Black,
		"red":       st.Red,
		"green":     st.Green,
		"yellow":    st.Yellow,
		"blue":      st.Blue,
		"magenta":   st.Magenta,
		"cyan":      st.Cyan,
		"white":     st.White,
		"inverse":   st.Inverse,
		"bold":      st.Bold,
		"italic":    st.Italic,
		"underline": st.Underline,
		"crossout":  st.Crossout,
	}
}