content: multi-doc index + tag filtering (index.sx) + 13 tests (710/710)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/content/conformance.sh

@@ -15,7 +15,7 @@ if [ ! -x "$SX_SERVER" ]; then
   fi
 fi
 
-SUITES=(block doc render api meta page page-full markdown text section compose tree-edit move clone query toc anchor outline flatten transform normalize find-replace stats summary table callout media data wire validate store snapshot crdt crdt-store sync md-import md-doc fed)
+SUITES=(block doc render api meta page page-full markdown text section compose tree-edit move clone query toc anchor outline flatten transform normalize find-replace stats summary index table callout media data wire validate store snapshot crdt crdt-store sync md-import md-doc fed)
 
 OUT_JSON="lib/content/scoreboard.json"
 OUT_MD="lib/content/scoreboard.md"
@@ -59,6 +59,7 @@ run_suite() {
 (load "lib/content/find-replace.sx")
 (load "lib/content/stats.sx")
 (load "lib/content/summary.sx")
+(load "lib/content/index.sx")
 (load "lib/content/table.sx")
 (load "lib/content/callout.sx")
 (load "lib/content/media.sx")

lib/content/index.sx

@@ -0,0 +1,51 @@
+;; content-on-sx — multi-document index.
+;;
+;; Projects a list of documents into summary cards (the blog index page), with
+;; tag filtering (category pages) and a tag cloud. Composes content/summary +
+;; doc metadata.
+;;
+;; Requires (loaded by harness): summary.sx (content/summary), meta.sx (doc-tags).
+
+(define
+  idx-in?
+  (fn
+    (x xs)
+    (cond
+      ((= (len xs) 0) false)
+      ((= (first xs) x) true)
+      (else (idx-in? x (rest xs))))))
+
+(define
+  idx-dedup
+  (fn
+    (xs seen)
+    (if
+      (= (len xs) 0)
+      (reverse seen)
+      (if
+        (idx-in? (first xs) seen)
+        (idx-dedup (rest xs) seen)
+        (idx-dedup (rest xs) (cons (first xs) seen))))))
+
+(define content/index (fn (docs) (map content/summary docs)))
+
+(define content/has-tag? (fn (doc tag) (idx-in? tag (doc-tags doc))))
+
+(define
+  content/index-by-tag
+  (fn
+    (docs tag)
+    (map content/summary (filter (fn (d) (content/has-tag? d tag)) docs))))
+
+(define
+  content/all-tags
+  (fn (docs) (idx-dedup (ct-flatmap-tags docs) (list))))
+
+(define
+  ct-flatmap-tags
+  (fn
+    (docs)
+    (if
+      (= (len docs) 0)
+      (list)
+      (append (doc-tags (first docs)) (ct-flatmap-tags (rest docs))))))

lib/content/scoreboard.json

@@ -24,6 +24,7 @@
     "find-replace": {"pass": 10, "fail": 0},
     "stats": {"pass": 17, "fail": 0},
     "summary": {"pass": 14, "fail": 0},
+    "index": {"pass": 13, "fail": 0},
     "table": {"pass": 15, "fail": 0},
     "callout": {"pass": 12, "fail": 0},
     "media": {"pass": 15, "fail": 0},
@@ -39,7 +40,7 @@
     "md-doc": {"pass": 12, "fail": 0},
     "fed": {"pass": 20, "fail": 0}
   },
-  "total_pass": 697,
+  "total_pass": 710,
   "total_fail": 0,
-  "total": 697
+  "total": 710
 }

lib/content/scoreboard.md

@@ -28,6 +28,7 @@ _Generated by `lib/content/conformance.sh`_
 | find-replace | 10 | 0 | 10 |
 | stats | 17 | 0 | 17 |
 | summary | 14 | 0 | 14 |
+| index | 13 | 0 | 13 |
 | table | 15 | 0 | 15 |
 | callout | 12 | 0 | 12 |
 | media | 15 | 0 | 15 |
@@ -42,4 +43,4 @@ _Generated by `lib/content/conformance.sh`_
 | md-import | 38 | 0 | 38 |
 | md-doc | 12 | 0 | 12 |
 | fed | 20 | 0 | 20 |
-| **Total** | **697** | **0** | **697** |
+| **Total** | **710** | **0** | **710** |

lib/content/tests/index.sx

@@ -0,0 +1,61 @@
+;; Extension — multi-document index + tag filtering.
+
+(st-bootstrap-classes!)
+(content/bootstrap!)
+(content-bootstrap-text!)
+
+(define
+  a
+  (doc-with-meta
+    (doc-append (doc-empty "a") (mk-text "p" "first post"))
+    {:title "A" :tags (list "sx" "news")}))
+(define
+  b
+  (doc-with-meta
+    (doc-append (doc-empty "b") (mk-text "p" "second post"))
+    {:title "B" :tags (list "news")}))
+(define
+  c
+  (doc-with-meta
+    (doc-append (doc-empty "c") (mk-text "p" "third"))
+    {:title "C" :tags (list "sx")}))
+(define docs (list a b c))
+
+;; ── index = list of summaries ──
+(define idx (content/index docs))
+(content-test "index count" (len idx) 3)
+(content-test
+  "index titles"
+  (map (fn (s) (get s :title)) idx)
+  (list "A" "B" "C"))
+(content-test
+  "index ids"
+  (map (fn (s) (get s :id)) idx)
+  (list "a" "b" "c"))
+(content-test "index excerpt" (get (first idx) :excerpt) "first post")
+
+;; ── has-tag? ──
+(content-test "has-tag yes" (content/has-tag? a "news") true)
+(content-test "has-tag no" (content/has-tag? c "news") false)
+
+;; ── index-by-tag (category page) ──
+(content-test
+  "by-tag news"
+  (map (fn (s) (get s :id)) (content/index-by-tag docs "news"))
+  (list "a" "b"))
+(content-test
+  "by-tag sx"
+  (map (fn (s) (get s :id)) (content/index-by-tag docs "sx"))
+  (list "a" "c"))
+(content-test "by-tag none" (content/index-by-tag docs "missing") (list))
+
+;; ── all-tags (tag cloud, deduped, document order) ──
+(content-test "all-tags" (content/all-tags docs) (list "sx" "news"))
+(content-test "all-tags empty" (content/all-tags (list)) (list))
+(content-test
+  "all-tags untagged"
+  (content/all-tags (list (doc-empty "x")))
+  (list))
+
+;; ── empty index ──
+(content-test "empty index" (content/index (list)) (list))

plans/content-on-sx.md

@@ -19,7 +19,7 @@ injected adapter, not core.
 
 ## Status (rolling)
 
-`bash lib/content/conformance.sh` → **697/697** (Phases 1–4 COMPLETE + ~32 extensions: HTML/SX escaping, Markdown render + import/export incl. tables & frontmatter (full round-trip), CRDT replication, tree-aware validation, snapshot cache, doc metadata, plain-text render, nested block trees + deep editing + flatten + relative reorder, doc stats + summary, table + callout + media blocks, HTML page wrapper + SEO page, doc composition + id-remap, portable data + wire serialization, block query + transforms + find/replace, TOC + anchored headings + outline, normalization)
+`bash lib/content/conformance.sh` → **710/710** (Phases 1–4 COMPLETE + ~33 extensions: HTML/SX escaping, Markdown render + import/export incl. tables & frontmatter (full round-trip), CRDT replication, tree-aware validation, snapshot cache, doc metadata, plain-text render, nested block trees + deep editing + flatten + relative reorder, doc stats + summary + multi-doc index, table + callout + media blocks, HTML page wrapper + SEO page, doc composition + id-remap, portable data + wire serialization, block query + transforms + find/replace, TOC + anchored headings + outline, normalization)
 
 ## Ground rules
 
@@ -92,6 +92,7 @@ lib/content/api.sx ── (content/edit) (content/render) (content/history) ─
 - [x] callout block (`callout.sx`: CtCallout note/warning/tip, renders html/sx/text/md, validated)
 - [x] media block (`media.sx`: CtMedia video/audio, renders html/sx/text/md, validated)
 - [x] list-card summary (`summary.sx`: content/summary — title/excerpt/words/reading/cover)
+- [x] multi-doc index (`index.sx`: content/index + index-by-tag + all-tags + has-tag?)
 - [x] HTML page wrapper (`page.sx`: content/page, escaped title from metadata)
 - [x] SEO page (`page-full.sx`: content/page-full, lang + meta description from excerpt)
 - [x] document composition (`compose.sx`: concat/prepend/concat-all/wrap-section)
@@ -111,6 +112,11 @@ lib/content/api.sx ── (content/edit) (content/render) (content/history) ─
 
 ## Progress log
 
+- 2026-06-07 — Extension: multi-document index (`index.sx`). `content/index`
+  projects a doc list into summary cards (blog index); `content/index-by-tag`
+  filters by tag (category pages); `content/all-tags` is a deduped tag cloud;
+  `content/has-tag?`. Composes content/summary + doc metadata. 13 tests; suite
+  710/710.
 - 2026-06-07 — Extension: list-card summary (`summary.sx`). `content/summary`
   returns `{:id :title :excerpt :words :reading-minutes :cover}` for index/listing
   cards, composing metadata + text + stats + query (`content/cover` = first