From 681b6ce5fb1c5d903f70bb81fb6f210689f0859e Mon Sep 17 00:00:00 2001
From: Syndamia <kamen@syndamia.com>
Date: Wed, 1 Jan 2025 14:43:58 +0200
Subject: feat(single): Implement fenced codeblocks

---
 single.awk | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

(limited to 'single.awk')

diff --git a/single.awk b/single.awk
index 0752b9f..94801be 100644
--- a/single.awk
+++ b/single.awk
@@ -15,7 +15,7 @@
 #     [ ] Definition lists
 #         [ ] Single line
 #         [ ] Multi-line
-#     [ ] Fenced code blocks ```lang ```
+#     [x] Fenced code blocks ```lang ```
 #     [ ] Tables
 #     [ ] Links
 #         [ ] Link destination (<link> inside anchors)
@@ -155,12 +155,22 @@ blockquote_level > 0 && empty0 {
 }
 /^>$/ { $0 = ""; not_paragraph = 1 }
 
+# Fenced code blocks
+fenced_codeblock {
+	$0 = "    " $0
+}
+
 # Code blocks (ending)
-inside_codeblock && ! /^[ \t]*$)/ {
+inside_codeblock && (/    ```/ || ! /^(    |\t|[ \t]*$)/) {
 	PNappnd("</code></pre>")
 	inside_codeblock = 0
 	emptyP1 = 1
 	not_paragraph = 1
+	if (fenced_codeblock) {
+		fenced_codeblock = 0
+		fenced_class = ""
+		next
+	}
 }
 
 # Lists
@@ -239,10 +249,20 @@ list_started && /^\[[x ]\][ \t]/ {
 	     "><label>" substr($0, 5) "</label>"
 }
 
-# Code blocks
-/^(    |\t)/ {
+# Fenced code blocks
+!inside_codeblock && /^[ \t]*```/ {
+	fenced_codeblock = 1
+
+	match(P1, /```[^ \t]*/)
+	if (RLENGTH > 3) {
+		fenced_class = " class=\"language-" tolower(substr(P1, RSTART + 3, RLENGTH - 3)) "\""
 	}
 
+	next
+}
+
+# Code blocks
+/^(    |\t)/ {
 	## Autoescape & and <
 	for (i = 1; match(substr($0, i), /&/); i += RSTART) {
 		RSTART += i - 1
@@ -251,8 +271,11 @@ list_started && /^\[[x ]\][ \t]/ {
 	gsub(/</, "\\&lt;")
 	gsub(/>/, "\\&gt;")
 
+	if (fenced_codeblock) {
+		$0 = substr($0, 5)
+	}
 	if (!inside_codeblock) {
-		$0 = "<pre><code>" $0
+		$0 = "<pre><code" fenced_class ">" $0
 		inside_codeblock = 1
 	}
 
-- 
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