Add support for tags in Discord -> Matrix formatter

formatter.go

@@ -1,3 +1,19 @@
+// mautrix-discord - A Matrix-Discord puppeting bridge.
+// Copyright (C) 2022 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 package main
 
 import (
@@ -13,14 +29,17 @@ import (
 	"maunium.net/go/mautrix/format/mdext"
 )
 
-var mdRenderer = goldmark.New(format.Extensions, format.HTMLOptions,
-	goldmark.WithExtensions(mdext.EscapeHTML, mdext.SimpleSpoiler, mdext.DiscordUnderline))
+var discordExtensions = goldmark.WithExtensions(mdext.EscapeHTML, mdext.SimpleSpoiler, mdext.DiscordUnderline)
 var escapeFixer = regexp.MustCompile(`\\(__[^_]|\*\*[^*])`)
 
-func renderDiscordMarkdown(text string) event.MessageEventContent {
+func (portal *Portal) renderDiscordMarkdown(text string) event.MessageEventContent {
 	text = escapeFixer.ReplaceAllStringFunc(text, func(s string) string {
 		return s[:2] + `\` + s[2:]
 	})
+	mdRenderer := goldmark.New(
+		format.Extensions, format.HTMLOptions, discordExtensions,
+		goldmark.WithExtensions(&DiscordTag{portal}),
+	)
 	return format.RenderMarkdownCustom(text, mdRenderer)
 }