1 files changed, 119 insertions, 0 deletions
diff --git a/tex/context/base/node-tst.lua b/tex/context/base/node-tst.lua
new file mode 100644
index 000000000..d7ea96f26
--- /dev/null
+++ b/tex/context/base/node-tst.lua
@@ -0,0 +1,119 @@
+if not modules then modules = { } end modules ['node-tst'] = {
+    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 glue    = node.id("glue")
+local penalty = node.id("penalty")
+local kern    = node.id("kern")
+local glyph   = node.id("glyph")
+local whatsit = node.id("whatsit")
+local hlist   = node.id("hlist")
+
+local find_node_tail = node.tail or node.slide
+
+local chardata = characters.data
+
+function nodes.the_left_margin(n) -- todo: three values
+    while n do
+        local id = n.id
+        if id == glue then
+            if n.subtype == 8 then -- 7 in c/web source
+                return n.spec.width
+            else
+                return 0
+            end
+        elseif id == whatsit then
+            n = n.next
+        elseif id == hlist then
+            return n.width
+        else
+            break
+        end
+    end
+    return 0
+end
+
+function nodes.the_right_margin(n)
+    if n then
+        n = find_node_tail(n)
+        while n do
+            local id = n.id
+            if id == glue then
+                if n.subtype == 9 then -- 8 in the c/web source
+                    return n.spec.width
+                else
+                    return 0
+                end
+            elseif id == whatsit then
+                n = n.prev
+            else
+                break
+            end
+        end
+    end
+    return false
+end
+
+function nodes.somespace(n,all)
+    if n then
+        local id = n.id
+        if id == glue then
+            return (all or (n.spec.width ~= 0)) and glue
+        elseif id == kern then
+            return (all or (n.kern ~= 0)) and kern
+        elseif id == glyph then
+            local category = chardata[n.char].category
+         -- maybe more category checks are needed
+            return (category == "zs") and glyph
+        end
+    end
+    return false
+end
+
+function nodes.somepenalty(n,value)
+    if n then
+        local id = n.id
+        if id == penalty then
+            if value then
+                return n.penalty == value
+            else
+                return true
+            end
+        end
+    end
+    return false
+end
+
+function nodes.is_display_math(head)
+    local n = head.prev
+    while n do
+        local id = n.id
+        if id == penalty then
+        elseif id == glue then
+            if n.subtype == 6 then -- above_display_short_skip
+                return true
+            end
+        else
+            break
+        end
+        n = n.prev
+    end
+    n = head.next
+    while n do
+        local id = n.id
+        if id == penalty then
+        elseif id == glue then
+            if n.subtype == 7 then -- below_display_short_skip
+                return true
+            end
+        else
+            break
+        end
+        n = n.next
+    end
+    return false
+end