From 40d6f8312a80bf927790a8fd69140630a3663735 Mon Sep 17 00:00:00 2001
From: James Mills <1290234+prologic@users.noreply.github.com>
Date: Sun, 26 Mar 2023 12:23:23 +1000
Subject: [PATCH] Add support for configurable extensions via -e/--extensions
 and configuration file

---
 .vscode/settings.json |  2 +
 main.go               | 97 ++++++++++++++++++++++++++++---------------
 2 files changed, 65 insertions(+), 34 deletions(-)

diff --git a/.vscode/settings.json b/.vscode/settings.json
index 638570e..94d2725 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -3,6 +3,7 @@
         "abhg",
         "alecthomas",
         "chromahtml",
+        "definitionlist",
         "errbuf",
         "Furqan",
         "goldmark",
@@ -15,6 +16,7 @@
         "sirupsen",
         "stefanfritsch",
         "Strikethrough",
+        "tasklist",
         "wikilink",
         "yuin",
         "ZSCONFIG",
diff --git a/main.go b/main.go
index 332efb9..836ca4e 100644
--- a/main.go
+++ b/main.go
@@ -64,8 +64,12 @@ README.md`
 // Ignore holds a set of patterns to ignore from parsing a .zsignore file
 var Ignore *ignore.GitIgnore
 
+// Parser holds a configured global instance of the goldmark markdown parser
+var Parser goldmark.Markdown
+
 var (
-	configFile string
+	configFile        string
+	enabledExtensions []string
 
 	// Title site title
 	Title string
@@ -80,9 +84,43 @@ var (
 	Production = false
 )
 
+// Extensions is a mapping of name to extension and the default set of extensions enabled
+// which can be overridden with -e/--extension or the extensions key
+// in ia config file such as .zs/config.yml
+var Extensions = map[string]goldmark.Extender{
+	"table":          extension.Table,
+	"strikethrough":  extension.Strikethrough,
+	"linkify":        extension.Linkify,
+	"tasklist":       extension.TaskList,
+	"definitionlist": extension.DefinitionList,
+	"footnote":       extension.Footnote,
+	"typography":     extension.Typographer,
+	"cjk":            extension.CJK,
+	"highlighting": highlighting.NewHighlighting(
+		highlighting.WithStyle("github"),
+		highlighting.WithFormatOptions(
+			chromahtml.WithLineNumbers(true),
+		),
+	),
+	"anchor":   &anchor.Extender{},
+	"d2":       &d2.Extender{},
+	"embed":    embed.New(),
+	"fences":   &fences.Extender{},
+	"wikilink": &wikilink.Extender{},
+}
+
 // Vars holds a map of global variables
 type Vars map[string]string
 
+// MapKeys returns a slice of keys from a map
+func MapKeys[K comparable, V any](m map[K]V) []K {
+	r := make([]K, 0, len(m))
+	for k := range m {
+		r = append(r, k)
+	}
+	return r
+}
+
 // NewTicker is a function that wraps a time.Ticker and ticks immediately instead of waiting for the first interval
 func NewTicker(d time.Duration) *time.Ticker {
 	ticker := time.NewTicker(d)
@@ -124,6 +162,28 @@ var RootCmd = &cobra.Command{
 			log.SetLevel(log.InfoLevel)
 		}
 
+		var extensions []goldmark.Extender
+		for _, name := range enabledExtensions {
+			if extender, valid := Extensions[name]; valid {
+				extensions = append(extensions, extender)
+			} else {
+				log.Warnf("invalid extension: %s", name)
+			}
+		}
+
+		Parser = goldmark.New(
+			goldmark.WithExtensions(extensions...),
+			goldmark.WithParserOptions(
+				parser.WithAttribute(),
+				parser.WithAutoHeadingID(),
+			),
+			goldmark.WithRendererOptions(
+				html.WithHardWraps(),
+				html.WithXHTML(),
+				html.WithUnsafe(),
+			),
+		)
+
 		return nil
 	},
 }
@@ -425,39 +485,7 @@ func buildMarkdown(path string, w io.Writer, vars Vars) error {
 	}
 
 	buf := &bytes.Buffer{}
-	gm := goldmark.New(
-		goldmark.WithExtensions(
-			extension.Table,
-			extension.Strikethrough,
-			extension.Linkify,
-			extension.TaskList,
-			extension.DefinitionList,
-			extension.Footnote,
-			extension.Typographer,
-			extension.CJK,
-			highlighting.NewHighlighting(
-				highlighting.WithStyle("github"),
-				highlighting.WithFormatOptions(
-					chromahtml.WithLineNumbers(true),
-				),
-			),
-			&anchor.Extender{},
-			&d2.Extender{},
-			embed.New(),
-			&fences.Extender{},
-			&wikilink.Extender{},
-		),
-		goldmark.WithParserOptions(
-			parser.WithAttribute(),
-			parser.WithAutoHeadingID(),
-		),
-		goldmark.WithRendererOptions(
-			html.WithHardWraps(),
-			html.WithXHTML(),
-			html.WithUnsafe(),
-		),
-	)
-	if err := gm.Convert([]byte(content), buf); err != nil {
+	if err := Parser.Convert([]byte(content), buf); err != nil {
 		return err
 	}
 	v["content"] = buf.String()
@@ -638,6 +666,7 @@ func init() {
 
 	RootCmd.PersistentFlags().BoolP("debug", "D", false, "enable debug logging $($ZS_DEBUG)")
 	RootCmd.PersistentFlags().StringVarP(&configFile, "config", "c", "", "config file (default: .zs/config.yml)")
+	RootCmd.PersistentFlags().StringSliceVarP(&enabledExtensions, "extensions", "e", MapKeys(Extensions), "override and enable specific extensions")
 	RootCmd.PersistentFlags().BoolVarP(&Production, "production", "p", false, "enable production mode ($ZS_PRODUCTION)")
 	RootCmd.PersistentFlags().StringVarP(&Title, "title", "t", "", "site title ($ZS_TITLE)")
 	RootCmd.PersistentFlags().StringVarP(&Description, "description", "d", "", "site description ($ZS_DESCRIPTION)")
-- 
2.43.0