1 files changed, 58 insertions, 0 deletions
diff --git a/tex/context/base/node-shp.lua b/tex/context/base/node-shp.lua
new file mode 100644
index 000000000..50b16efa5
--- /dev/null
+++ b/tex/context/base/node-shp.lua
@@ -0,0 +1,58 @@
+if not modules then modules = { } end modules ['node-shp'] = {
+    version   = 1.001,
+    comment   = "companion to node-ini.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+local hlist = node.id('hlist')
+local vlist = node.id('vlist')
+local disc  = node.id('disc')
+local mark  = node.id('mark')
+local kern  = node.id('kern')
+local glue  = node.id('glue')
+
+local free_node   = node.free
+local remove_node = node.remove
+
+local function cleanup_page(head) -- rough
+    local start = head
+    while start do
+        local id = start.id
+        if id == disc or (id == glue and not start.writable) or (id == kern and start.kern == 0) or id == mark then
+            head, start, tmp = remove_node(head,start)
+            free_node(tmp)
+        elseif id == hlist or id == vlist then
+            local sl = start.list
+            if sl then
+                start.list = cleanup_page(sl)
+                start = start.next
+            else
+                head, start, tmp = remove_node(head,start)
+                free_node(tmp)
+            end
+        else
+            start = start.next
+        end
+    end
+    return head
+end
+
+nodes.cleanup_page_first = false
+
+function nodes.cleanup_page(head)
+    -- about 10% of the nodes make no sense for the backend
+    if nodes.cleanup_page_first then
+        head = cleanup_page(head)
+    end
+    return head, false
+end
+
+local actions = tasks.actions("shipouts",0)  -- no extra arguments
+
+function nodes.process_page(head) -- problem, attr loaded before node, todo ...
+    return actions(head)
+end
+
+--~ nodes.process_page = actions