feat: ansi text formats

resolves #440

docs/docs/configuration.md

@@ -335,6 +335,17 @@ Oh my Posh mainly supports three different color types being
 
   `darkGray` `lightRed` `lightGreen` `lightYellow` `lightBlue` `lightMagenta` `lightCyan` `lightWhite`
 
+### Text decorations
+
+You can make use of the following syntax to decorate text:
+
+- `<b>bold</b>`: renders `bold` as bold text
+- `<u>underline</u>`: renders `underline` as underlined text
+- `<i>italic</i>`: renders `italic` as italic text
+- `<s>strikethrough</s>`: renders `strikethrough` as strikethrough text
+
+This can be used in templates and icons/text inside your config.
+
 ### Hyperlinks
 
 The engine has the ability to render hyperlinks. Your terminal has to support it and the option

src/ansi_color.go

@@ -92,6 +92,7 @@ func (a *AnsiColor) writeAndRemoveText(background, foreground, text, textToRemov
 }
 
 func (a *AnsiColor) write(background, foreground, text string) {
+	text = a.formats.formatText(text)
 	// first we match for any potentially valid colors enclosed in <>
 	match := findAllNamedRegexMatch(`<(?P<foreground>[^,>]+)?,?(?P<background>[^>]+)?>(?P<content>[^<]*)<\/>`, text)
 	for i := range match {

src/ansi_formats.go

@@ -24,6 +24,10 @@ type ansiFormats struct {
 	escapeRight           string
 	hyperlink             string
 	osc99                 string
+	bold                  string
+	italic                string
+	underline             string
+	strikethrough         string
 }
 
 func (a *ansiFormats) init(shell string) {
@@ -45,6 +49,10 @@ func (a *ansiFormats) init(shell string) {
 		a.escapeRight = "%}"
 		a.hyperlink = "%%{\x1b]8;;%s\x1b\\%%}%s%%{\x1b]8;;\x1b\\%%}"
 		a.osc99 = "%%{\x1b]9;9;%s\x1b\\%%}"
+		a.bold = "%%{\x1b[1m%%}%s%%{\x1b[22m%%}"
+		a.italic = "%%{\x1b[3m%%}%s%%{\x1b[23m%%}"
+		a.underline = "%%{\x1b[4m%%}%s%%{\x1b[24m%%}"
+		a.strikethrough = "%%{\x1b[9m%%}%s%%{\x1b[29m%%}"
 	case bash:
 		a.linechange = "\\[\x1b[%d%s\\]"
 		a.left = "\\[\x1b[%dC\\]"
@@ -61,6 +69,10 @@ func (a *ansiFormats) init(shell string) {
 		a.escapeRight = "\\]"
 		a.hyperlink = "\\[\x1b]8;;%s\x1b\\\\\\]%s\\[\x1b]8;;\x1b\\\\\\]"
 		a.osc99 = "\\[\x1b]9;9;%s\x1b\\\\\\]"
+		a.bold = "\\[\x1b[1m\\]%s\\[\x1b[22m\\]"
+		a.italic = "\\[\x1b[3m\\]%s\\[\x1b[23m\\]"
+		a.underline = "\\[\x1b[4m\\]%s\\[\x1b[24m\\]"
+		a.strikethrough = "\\[\x1b[9m\\]%s\\[\x1b[29m\\]"
 	default:
 		a.linechange = "\x1b[%d%s"
 		a.left = "\x1b[%dC"
@@ -77,6 +89,11 @@ func (a *ansiFormats) init(shell string) {
 		a.escapeRight = ""
 		a.hyperlink = "\x1b]8;;%s\x1b\\%s\x1b]8;;\x1b\\"
 		a.osc99 = "\x1b]9;9;%s\x1b\\"
+		a.bold = "\x1b[1m%s\x1b[22m"
+		a.italic = "\x1b[3m%s\x1b[23m"
+		a.underline = "\x1b[4m%s\x1b[24m"
+		a.strikethrough = "\x1b[9m%s\x1b[29m"
+		a.strikethrough = "\x1b[9m%s\x1b[29m"
 	}
 }
 
@@ -106,3 +123,22 @@ func (a *ansiFormats) generateHyperlink(text string) string {
 	// replace original text by the new one
 	return strings.Replace(text, results["all"], hyperlink, 1)
 }
+
+func (a *ansiFormats) formatText(text string) string {
+	results := findAllNamedRegexMatch("(?P<context><(?P<format>[buis])>(?P<text>[^<]+)</[buis]>)", text)
+	for _, result := range results {
+		var formatted string
+		switch result["format"] {
+		case "b":
+			formatted = fmt.Sprintf(a.bold, result["text"])
+		case "u":
+			formatted = fmt.Sprintf(a.underline, result["text"])
+		case "i":
+			formatted = fmt.Sprintf(a.italic, result["text"])
+		case "s":
+			formatted = fmt.Sprintf(a.strikethrough, result["text"])
+		}
+		text = strings.Replace(text, result["context"], formatted, 1)
+	}
+	return text
+}

src/ansi_formats_test.go

@@ -77,3 +77,23 @@ func TestGenerateHyperlinkWithUrlNoName(t *testing.T) {
 		assert.Equal(t, tc.Expected, hyperlinkText)
 	}
 }
+
+func TestFormatText(t *testing.T) {
+	cases := []struct {
+		Case     string
+		Text     string
+		Expected string
+	}{
+		{Case: "single format", Text: "This <b>is</b> white", Expected: "This \x1b[1mis\x1b[22m white"},
+		{Case: "double format", Text: "This <b>is</b> white, this <b>is</b> orange", Expected: "This \x1b[1mis\x1b[22m white, this \x1b[1mis\x1b[22m orange"},
+		{Case: "underline", Text: "This <u>is</u> white", Expected: "This \x1b[4mis\x1b[24m white"},
+		{Case: "italic", Text: "This <i>is</i> white", Expected: "This \x1b[3mis\x1b[23m white"},
+		{Case: "strikethrough", Text: "This <s>is</s> white", Expected: "This \x1b[9mis\x1b[29m white"},
+	}
+	for _, tc := range cases {
+		a := ansiFormats{}
+		a.init("")
+		formattedText := a.formatText(tc.Text)
+		assert.Equal(t, tc.Expected, formattedText, tc.Case)
+	}
+}