content: render boundary (asHTML/asSx polymorphic) + 29 tests

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

lib/content/render.sx

@@ -0,0 +1,78 @@
+;; content-on-sx — render boundary.
+;;
+;; Rendering is a message, not a property switch: every block (and the document)
+;; answers asHTML and asSx. The internal model carries no presentation — the
+;; boundary format is chosen by which message you send. The document folds its
+;; children's renderings, so (asHTML doc) / (asSx doc) are pure polymorphic
+;; sends with no type dispatch in the SX layer.
+;;
+;; NOTE: no HTML escaping yet — text is emitted verbatim. Escaping is a boundary
+;; concern to add before any untrusted content reaches render.
+
+(define
+  content-bootstrap-render!
+  (fn
+    ()
+    (begin
+      (ct-def-method!
+        "CtHeading"
+        "asHTML"
+        "asHTML | t | t := level printString. ^ '<h' , t , '>' , text , '</h' , t , '>'")
+      (ct-def-method! "CtText" "asHTML" "asHTML ^ '<p>' , text , '</p>'")
+      (ct-def-method!
+        "CtCode"
+        "asHTML"
+        "asHTML ^ '<pre><code class=\"language-' , language , '\">' , text , '</code></pre>'")
+      (ct-def-method!
+        "CtQuote"
+        "asHTML"
+        "asHTML ^ '<blockquote>' , text , '</blockquote>'")
+      (ct-def-method!
+        "CtImage"
+        "asHTML"
+        "asHTML ^ '<img src=\"' , src , '\" alt=\"' , alt , '\">'")
+      (ct-def-method!
+        "CtEmbed"
+        "asHTML"
+        "asHTML ^ '<iframe src=\"' , url , '\"></iframe>'")
+      (ct-def-method! "CtDivider" "asHTML" "asHTML ^ '<hr>'")
+      (ct-def-method!
+        "CtList"
+        "asHTML"
+        "asHTML | tag | tag := ordered ifTrue: ['ol'] ifFalse: ['ul']. ^ '<' , tag , '>' , (items inject: '' into: [:a :x | a , '<li>' , x , '</li>']) , '</' , tag , '>'")
+      (ct-def-method!
+        "CtDoc"
+        "asHTML"
+        "asHTML ^ blocks inject: '' into: [:a :b | a , (b asHTML)]")
+      (ct-def-method!
+        "CtHeading"
+        "asSx"
+        "asSx | t | t := level printString. ^ '(h' , t , ' \"' , text , '\")'")
+      (ct-def-method! "CtText" "asSx" "asSx ^ '(p \"' , text , '\")'")
+      (ct-def-method! "CtCode" "asSx" "asSx ^ '(pre (code \"' , text , '\"))'")
+      (ct-def-method! "CtQuote" "asSx" "asSx ^ '(blockquote \"' , text , '\")'")
+      (ct-def-method!
+        "CtImage"
+        "asSx"
+        "asSx ^ '(img :src \"' , src , '\" :alt \"' , alt , '\")'")
+      (ct-def-method! "CtEmbed" "asSx" "asSx ^ '(iframe :src \"' , url , '\")'")
+      (ct-def-method! "CtDivider" "asSx" "asSx ^ '(hr)'")
+      (ct-def-method!
+        "CtList"
+        "asSx"
+        "asSx | tag | tag := ordered ifTrue: ['ol'] ifFalse: ['ul']. ^ '(' , tag , ' ' , (items inject: '' into: [:a :x | a , '(li \"' , x , '\")']) , ')'")
+      (ct-def-method!
+        "CtDoc"
+        "asSx"
+        "asSx ^ '(article ' , (blocks inject: '' into: [:a :b | a , (b asSx)]) , ')'")
+      true)))
+
+;; ── SX boundary API — pure message sends ──
+(define asHTML (fn (node) (str (st-send node "asHTML" (list)))))
+(define asSx (fn (node) (str (st-send node "asSx" (list)))))
+
+;; readable aliases
+(define render-html asHTML)
+(define render-sx asSx)
+(define block-html asHTML)
+(define block-sx asSx)