From 65069abba06212316af016fc14953e4dbdba3119 Mon Sep 17 00:00:00 2001
From: frozolotl <frozolotl@protonmail.com>
Date: Mon, 29 Jan 2024 00:41:59 +0100
Subject: [PATCH 1/3] Unescape escaped backticks and switch to ZWJ

---
 bot/src/bot.rs | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/bot/src/bot.rs b/bot/src/bot.rs
index 28bc528..84fd2da 100644
--- a/bot/src/bot.rs
+++ b/bot/src/bot.rs
@@ -12,10 +12,11 @@ use tokio::sync::{mpsc, Mutex};
 use crate::worker::Worker;
 use crate::SOURCE_URL;
 
-/// Prevent garbled output from codeblocks unwittingly terminated by their own content.
-///
-/// U+200C is a zero-width non-joiner.
+/// U+200D is a zero-width joiner.
 /// It prevents the triple backtick from being interpreted as a codeblock but retains ligature support.
+const ZERO_WIDTH_JOINER: char = '\u{200D}';
+
+/// Prevent garbled output from codeblocks unwittingly terminated by their own content.
 fn sanitize_code_block(raw: &str) -> impl Display + '_ {
 	struct Helper<'a>(&'a str);
 
@@ -27,7 +28,9 @@ fn sanitize_code_block(raw: &str) -> impl Display + '_ {
 					.map_or((section, false), |safe| (safe, true));
 				formatter.write_str(safe)?;
 				if should_append {
-					formatter.write_str("``\u{200c}`")?;
+					formatter.write_str("``")?;
+					formatter.write_char(ZERO_WIDTH_JOINER)?;
+					formatter.write_str("`")?;
 				}
 			}
 
@@ -254,6 +257,16 @@ impl<'a> poise::PopArgument<'a> for CodeBlock {
 		if code_block.language.as_deref() == Some("ansi") {
 			source = strip_ansi_escapes::strip_str(source);
 		}
+
+		// Remove all occurences of the ZWJ when used if surrounded by backticks.
+		// This is used to enter Typst code blocks within Discord-markdown code blocks.
+		// Two replace calls are needed to remove all patterns of `ABA`: ABABABA => AABAA => AAAA.
+		let pattern = format!("`{ZERO_WIDTH_JOINER}`");
+		let replacement = "``";
+		source = source
+			.replace(&pattern, replacement)
+			.replace(&pattern, replacement);
+
 		Ok((rest, attachment_index, CodeBlock { source }))
 	}
 }

From 910be400b6a4b18478c1521f7261485f412366b7 Mon Sep 17 00:00:00 2001
From: frozolotl <frozolotl@protonmail.com>
Date: Mon, 29 Jan 2024 00:51:18 +0100
Subject: [PATCH 2/3] Improve wording

---
 bot/src/bot.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bot/src/bot.rs b/bot/src/bot.rs
index 84fd2da..5f0d63a 100644
--- a/bot/src/bot.rs
+++ b/bot/src/bot.rs
@@ -258,7 +258,7 @@ impl<'a> poise::PopArgument<'a> for CodeBlock {
 			source = strip_ansi_escapes::strip_str(source);
 		}
 
-		// Remove all occurences of the ZWJ when used if surrounded by backticks.
+		// Remove all occurences of zero width joiners surrounded by backticks.
 		// This is used to enter Typst code blocks within Discord-markdown code blocks.
 		// Two replace calls are needed to remove all patterns of `ABA`: ABABABA => AABAA => AAAA.
 		let pattern = format!("`{ZERO_WIDTH_JOINER}`");

From 6eb507e134b187c09a04d3659af92e598664147c Mon Sep 17 00:00:00 2001
From: Matt Fellenz <matt@felle.nz>
Date: Sun, 28 Jan 2024 15:55:45 -0800
Subject: [PATCH 3/3] Clean up

---
 bot/src/bot.rs | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/bot/src/bot.rs b/bot/src/bot.rs
index 84fd2da..1bf548f 100644
--- a/bot/src/bot.rs
+++ b/bot/src/bot.rs
@@ -28,9 +28,7 @@ fn sanitize_code_block(raw: &str) -> impl Display + '_ {
 					.map_or((section, false), |safe| (safe, true));
 				formatter.write_str(safe)?;
 				if should_append {
-					formatter.write_str("``")?;
-					formatter.write_char(ZERO_WIDTH_JOINER)?;
-					formatter.write_str("`")?;
+					write!(formatter, "``{ZERO_WIDTH_JOINER}`")?;
 				}
 			}
 
@@ -221,13 +219,13 @@ To remove the preamble entirely, use `pagesize=default theme=transparent`.
 ```
 ?render `hello, world!`
 
-?render pagesize=default theme=light ``‌`
+?render pagesize=default theme=light ``‍`
 = Heading!
 
 And some text.
 
 #lorem(100)
-``‌`
+``‍`
 
 ?render `#myfunc()` I don't understand this code, can anyone help?
 ```"
@@ -258,7 +256,7 @@ impl<'a> poise::PopArgument<'a> for CodeBlock {
 			source = strip_ansi_escapes::strip_str(source);
 		}
 
-		// Remove all occurences of the ZWJ when used if surrounded by backticks.
+		// Remove all occurrences of the ZWJ when used if surrounded by backticks.
 		// This is used to enter Typst code blocks within Discord-markdown code blocks.
 		// Two replace calls are needed to remove all patterns of `ABA`: ABABABA => AABAA => AAAA.
 		let pattern = format!("`{ZERO_WIDTH_JOINER}`");
@@ -401,13 +399,13 @@ async fn source(ctx: Context<'_>) -> Result<(), PoiseError> {
 /// ```
 /// ?ast `hello, world!`
 ///
-/// ?ast ``‌`
+/// ?ast ``‍`
 /// = Heading!
 ///
 /// And some text.
 ///
 /// #lorem(100)
-/// ``‌`
+/// ``‍`
 ///
 /// ?ast `#((3): 4)` Interesting parse result here.
 /// ```