appview: pages/markup: setup package for markdown and other markups

appview/pages/markdown.go appview/pages/markup/markdown.go

···
-package pages
+// Package markup is an umbrella package for all markups and their renderers.
+package markup
 
 import (
 	"bytes"
···
 	"github.com/yuin/goldmark/parser"
 )
 
-func renderMarkdown(source string) string {
+func RenderMarkdown(source string) string {
 	md := goldmark.New(
 		goldmark.WithExtensions(extension.GFM),
 		goldmark.WithParserOptions(

appview/pages/markup/readme.go

···
+package markup
+
+import "strings"
+
+type Format string
+
+const (
+	FormatMarkdown Format = "markdown"
+	FormatText     Format = "text"
+)
+
+var FileTypes map[Format][]string = map[Format][]string{
+	FormatMarkdown: []string{".md", ".markdown", ".mdown", ".mkdn", ".mkd"},
+}
+
+func GetFormat(filename string) Format {
+	for format, extensions := range FileTypes {
+		for _, extension := range extensions {
+			if strings.HasSuffix(filename, extension) {
+				return format
+			}
+		}
+	}
+	// default format
+	return FormatText
+}