first try at head-body separation

arvo/eyre.hoon

@@ -382,23 +382,6 @@
         urb.wreq.abort() // trigger keep
       }
     }
-    urb.waspElem = function(ele){
-      url = ele.src || ele.href
-      if(!url || (new URL(url)).host != document.location.host)
-        return;
-      urb.waspUrl(url)
-    }
-    urb.waspUrl = function(url){
-      var xhr = new XMLHttpRequest()
-      xhr.open("HEAD", url)
-      xhr.send()
-      xhr.onload = urb.waspLoadedXHR
-    }
-    urb.waspLoadedXHR = function(){urb.wasp(urb.getXHRWasp(this))}
-    urb.getXHRWasp = function(xhr){
-      var dep = xhr.getResponseHeader("etag")
-      if(dep) return JSON.parse(dep.substr(2))
-    }
 
     '''
   ::

lib/urb-split.hoon

@@ -0,0 +1,9 @@
+::
+::::  /hoon/urb-split/lib
+  ::
+|=  [dep=@uvH urb=manx]  ^-  [hed=[@uvh marl] bod=[@uvH marl]]
+~|  [%malformed-urb urb]  :: XX types
+?>  ?=([[%html ~] [[%head ~] *] [[%body ~] *] ~] urb)
+=+  `[[%html ~] [[%head ~] hed=marl] [[%body ~] bod=marl] ~]`urb
+:-  [dep hed]                         :: Assume all dependencies are hard
+[0v0 bod]

mar/urb.hoon

@@ -2,13 +2,13 @@
 ::::  /hoon/urb/mar
   ::
 /?  314
+/=  urb-wasp-data-js    /:    /%/wasp-data    /js/
 !:
-|_  [dep=@uvH own=[[%html ~] [[%head ~] hed=marl] [[%body ~] tal=marl] ~]]
-::
-++  etag-js
+|_  [[dep=@uvH hed=marl] [dep-bod=@uvH bod=marl]]
+++  linked-deps-js
   '''
   urb.waspAll = function(sel){
-    Array.prototype.map.call(document.querySelectorAll(sel), urb.waspElem)
+    [].map.call(document.querySelectorAll(sel), urb.waspElem)
   }
   if(urb.wasp){urb.waspAll('script'); urb.waspAll('link')}
   '''
@@ -18,11 +18,23 @@
   ++  html  (crip (poxo hymn))                          ::  convert to %html
   ++  hymn                                              ::  inject dependencies
     ^-  manx
-    =:  hed.own  :_(hed.own ;meta(charset "utf-8", urb_injected "");)
-        tal.own  (welp tal.own ;script(urb_injected ""):"{(trip etag-js)}" ~)
+    ;html
+      ;head
+        ;meta(charset "utf-8", urb_injected "");
+        ;*  ?~  dep  ~
+            :~  ;script@"/~/on/{<dep>}.js"(urb_injected "");  
+                ;script(urb_injected "")
+                  ;-  (trip urb-wasp-data-js)
+                  ;-  "urb.waspData({(pojo %s (scot %uv dep-bod))})"
+                ==
+            ==
+        ;*  hed
       ==
-    ?~  dep  own
-    own(hed :_(hed.own ;script@"/~/on/{<dep>}.js"(urb_injected "");))
+      ;body
+        ;*  bod
+        ;script(urb_injected ""):"{(trip linked-deps-js)}"
+      ==
+    ==
   --
 ++  grab  
   |%                                                    ::  convert from

mar/urb/wasp-data.js

@@ -0,0 +1,30 @@
+urb.waspElem = function(ele){
+  url = ele.src || ele.href
+  if(!url || (new URL(url)).host != document.location.host)
+    return;
+  urb.waspUrl(url)
+}
+urb.waspUrl = function(url){
+  var xhr = new XMLHttpRequest()
+  xhr.open("HEAD", url)
+  xhr.send()
+  xhr.onload = urb.waspLoadedXHR
+}
+urb.waspLoadedXHR = function(){urb.wasp(urb.getXHRWasp(this))}
+urb.getXHRWasp = function(xhr){
+  var dep = xhr.getResponseHeader("etag")
+  if(dep) return JSON.parse(dep.substr(2))
+}
+
+urb.datadeps = {}
+urb.waspData = function(dep){
+  urb.datadeps[dep] = true
+  urb.wasp(dep)
+}
+urb.ondataupdate = urb.onupdate  // overridable
+
+var _onupdate = urb.onupdate
+urb.onupdate = function(dep){
+  if(urb.datadeps[dep]) urb.ondataupdate(dep)
+  else _onupdate(dep)
+}

ren/tree/body.hoon

@@ -0,0 +1,14 @@
+::
+::::  /hoon/body/tree/ren
+  ::
+/?    314
+/=    dat    /%  /tree-json/ :: default include
+^-  marl
+;=  ;script(type "text/javascript"): window.tree = {(pojo (joba %data dat))}
+    ;div.container
+      ;div.row#main
+        ;div#head;
+        ;div#body;
+      ==
+    ==
+==

ren/tree/head.hoon

@@ -1,10 +1,8 @@
 ::
-::::  /hoon/hymn/tree/ren
+::::  /hoon/head/tree/ren
   ::
 ::
 /?    314
-/-    tree-include
-/=    dat    /%  /tree-json/ :: default include
 /=    tub    /$  |=([bem=beam *] (flop s.bem))
 /=    aut
   /$  %+  cork  fuel                                    :: after parsing params,
@@ -15,9 +13,8 @@
 !:
 ::::
   ::
-;html
-  ;head
-    ;title: Tree
+^-  marl
+;=  ;title: Tree
     ;meta(name "viewport", content "width=device-width, initial-scale=1");
     ;link(type "text/css", rel "stylesheet", href "//cdnjs.cloudflare.com/ajax/libs/codemirror/4.3.0/codemirror.min.css");
     ;link(type "text/css", rel "stylesheet", href "/lib/css/fonts.css");
@@ -39,14 +36,4 @@
       "codemirror/4.3.0/mode/markdown/markdown.min.js");
     ;script(type "text/javascript", src "{?.(aut "" "/~~")}".
                                         "/~/at/lib/js/urb.js");
-  ==
-  ;body
-    ;script(type "text/javascript"): window.tree = {(pojo (joba %data dat))}
-    ;div.container
-      ;div.row#main
-        ;div#head;
-        ;div#body;
-      ==
-    ==
-  ==
 ==

ren/urb.hoon

@@ -1,10 +1,11 @@
 ::
 ::::  /hoon/urb/ren
   ::
-/#    /%
-    /^  [[%html ~] [[%head ~] hed=marl] [[%body ~] tal=marl] ~]
-    /,
-        /web/app   /|(/!hymn/ /tree-hymn/)
-        /      /tree-hymn/
-    ==
+/+    urb-split    :: for single-page apps
+/%    /^  [hed=[@uvH marl] bod=[@uvH marl]]
+      /,      /web/app
+          /|(/;urb-split;/#/!hymn/ /urb-tree/)
+              /
+          /urb-tree/
+      ==
 -.-

ren/urb/tree.hoon

@@ -0,0 +1,8 @@
+::  Combine /tree-head/ and /tree-body/
+::
+::::  /hoon/urb/ren
+  ::
+/=   hed    /#    /%   /:  /===/ren   /tree-head/  :: XX static
+/=   bod    /#    /%   /tree-body/
+^-  [hed=[@uvH marl] bod=[@uvH marl]]
+[hed bod]