From faec1f84ed1e9e8ee78055796a8ebc92936abe9d Mon Sep 17 00:00:00 2001
From: Adam Soltys <adam@coinos.io>
Date: Fri, 9 Oct 2026 21:48:11 -0700
Subject: Posts: inline markdown. **bold** / __bold__, *italic* / _italic_,
 ***both***, ~~struck~~ and `code` render in a post's plain text — what
 newsletter bots and Amethyst users type and Amethyst shows; we showed the
 asterisks. Strict about edges, so snake_case, x__init__y, 2*3*4, "$5 * 2" and
 a lone star stay as typed, and markers never reach across a link, mention or
 hashtag. No headings or lists in posts: "#" at a line's start is a hashtag
 here, and articles render their own headings. tools/post-markdown-test.js
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Vps2H27rhbG9ZqseGfMrc3
---
 src/features/messages.js | 28 ++++++++++++++++++++++++++--
 src/style.css            |  2 ++
 2 files changed, 28 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/features/messages.js b/src/features/messages.js
index c803d4d..06371cf 100644
--- a/src/features/messages.js
+++ b/src/features/messages.js
@@ -8016,6 +8016,30 @@ export function messagesFeature(ctx) {
   // `em` is the event's own ["emoji", code, url] map (NIP-30): a :code: it
   // names becomes its picture, any other :code: stays text — a message
   // never borrows pictures from packs the READER happens to hold.
+  // Inline markdown in a post's plain text, the subset people actually type
+  // and Amethyst already shows: **bold** / __bold__, *italic* / _italic_,
+  // ~~struck~~ and `code`. Strict about edges so snake_case, 2*3*4 and a lone
+  // asterisk stay as typed; markers never reach across a link, mention or
+  // hashtag (those are split out first). No headings or lists in posts —
+  // "#" at a line's start is a hashtag here, and articles have their own.
+  const MD_INLINE = /(`[^`\n]+`)|(\*\*\*(?=\S)[^\n]*?\S\*\*\*)|(\*\*(?=\S)[^\n]*?\S\*\*)|((?<![\p{L}\p{N}_])__(?=\S)[^\n]*?\S__(?![\p{L}\p{N}_]))|(~~(?=\S)[^\n]*?\S~~)|((?<![\p{L}\p{N}*])\*(?=[^\s*])[^*\n]*?[^\s*]\*(?![\p{L}\p{N}*]))|((?<![\p{L}\p{N}_])_(?=[^\s_])[^_\n]*?[^\s_]_(?![\p{L}\p{N}_]))/u;
+  function mdInline(str) {
+    const out = [];
+    let rest = String(str);
+    for (let guard = 0; rest && guard < 200; guard++) {
+      const m = MD_INLINE.exec(rest);
+      if (!m) { out.push(rest); break; }
+      if (m.index) out.push(rest.slice(0, m.index));
+      const tok = m[0];
+      if (m[1]) out.push(h('code', { class: 'md-code' }, tok.slice(1, -1)));
+      else if (m[2]) out.push(h('strong', {}, h('em', {}, ...mdInline(tok.slice(3, -3)))));
+      else if (m[3] || m[4]) out.push(h('strong', {}, ...mdInline(tok.slice(2, -2))));
+      else if (m[5]) out.push(h('s', {}, ...mdInline(tok.slice(2, -2))));
+      else out.push(h('em', {}, ...mdInline(tok.slice(1, -1))));
+      rest = rest.slice(m.index + tok.length);
+    }
+    return out;
+  }
   function noteBody(text, depth = 0, em = null) {
     const out = [];
     const emojiAt = em && em.size ? (c) => em.get(c) : null;
@@ -8062,8 +8086,8 @@ export function messagesFeature(ctx) {
           onClick: (e) => { e.preventDefault(); e.stopPropagation(); openTopicFeed(part.slice(1)); },
         }, part));
       } else if (emojiAt && part.includes(':')) {
-        for (const p of splitEmoji(part, emojiAt)) out.push(typeof p === 'string' ? p : emojiImg(p.code, p.url));
-      } else out.push(part);
+        for (const p of splitEmoji(part, emojiAt)) out.push(...(typeof p === 'string' ? mdInline(p) : [emojiImg(p.code, p.url)]));
+      } else out.push(...mdInline(part));
     }
     return out;
   }
diff --git a/src/style.css b/src/style.css
index 5e3ddd7..8d41124 100644
--- a/src/style.css
+++ b/src/style.css
@@ -1628,3 +1628,5 @@ body::after {
 .mention-ac { display: flex; flex-direction: column; border: 1px solid var(--line); border-radius: 10px; background: var(--paper); overflow: hidden; max-height: 280px; overflow-y: auto; }
 .mention-ac:empty { display: none; }
 .mention-ac .item { cursor: pointer; padding: 6px 10px; }
+/* `code` in a post */
+.md-code { font-family: var(--mono, ui-monospace, monospace); font-size: .9em; background: color-mix(in srgb, currentColor 9%, transparent); border-radius: 4px; padding: 0 .3em; }
-- 
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