From 5e668aa418d6d082446e9369ae06625b50e49943 Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Tue, 6 Jun 2017 13:57:28 +0200
Subject: 2017-06-06 13:28:00

---
 tex/context/base/mkiv/math-noa.lua | 100 +++++++++++++++++++++----------------
 1 file changed, 57 insertions(+), 43 deletions(-)

(limited to 'tex/context/base/mkiv/math-noa.lua')

diff --git a/tex/context/base/mkiv/math-noa.lua b/tex/context/base/mkiv/math-noa.lua
index 8b1fa87fd..abc5337c6 100644
--- a/tex/context/base/mkiv/math-noa.lua
+++ b/tex/context/base/mkiv/math-noa.lua
@@ -1525,30 +1525,30 @@ mathpairs[0x222C] = { [0x222B] = 0x222D }
 mathpairs[0x007C] = { [0x007C] = 0x2016, [0x2016] = 0x2980 } -- bar+bar=double bar+double=triple
 mathpairs[0x2016] = { [0x007C] = 0x2980, [0x02B9] = 0x2016 } -- double+bar=triple
 
--- local movesub = {
---     -- primes
---     [0x2032] = 0xFE932,
---     [0x2033] = 0xFE933,
---     [0x2034] = 0xFE934,
---     [0x2057] = 0xFE957,
---     -- reverse primes
---     [0x2035] = 0xFE935,
---     [0x2036] = 0xFE936,
---     [0x2037] = 0xFE937,
--- }
-
 local movesub = {
     -- primes
-    [0x2032] = 0x2032,
-    [0x2033] = 0x2033,
-    [0x2034] = 0x2034,
-    [0x2057] = 0x2057,
+    [0x2032] = 0xFE932,
+    [0x2033] = 0xFE933,
+    [0x2034] = 0xFE934,
+    [0x2057] = 0xFE957,
     -- reverse primes
-    [0x2035] = 0x2035,
-    [0x2036] = 0x2036,
-    [0x2037] = 0x2037,
+    [0x2035] = 0xFE935,
+    [0x2036] = 0xFE936,
+    [0x2037] = 0xFE937,
 }
 
+-- local movesub = {
+--     -- primes
+--     [0x2032] = 0x2032,
+--     [0x2033] = 0x2033,
+--     [0x2034] = 0x2034,
+--     [0x2057] = 0x2057,
+--     -- reverse primes
+--     [0x2035] = 0x2035,
+--     [0x2036] = 0x2036,
+--     [0x2037] = 0x2037,
+-- }
+
 -- inner under over vcenter
 
 local validpair = {
@@ -1563,38 +1563,48 @@ local validpair = {
     [noad_opnolimits]      = true,
 }
 
-local function movesubscript(parent,current_nucleus,current_char)
+local options_supported = tokens.defined("Unosuperscript")
+
+local function fixsupscript(parent,current,current_char,new_char)
+    if new_char ~= current_char and new_char ~= true then
+        setchar(current,new_char)
+        if trace_collapsing then
+            report_collapsing("fixing subscript, replacing supscript %U by %U",current_char,new_char)
+        end
+    else
+        if trace_collapsing then
+            report_collapsing("fixing subscript, supscript %U",current_char)
+        end
+    end
+    if options_supported then
+        setfield(parent,"options",0x08+0x22)
+    end
+end
+
+local function movesubscript(parent,current_nucleus,current_char,new_char)
     local prev = getprev(parent)
     if prev and getid(prev) == math_noad then
         local psup = getsup(prev)
         local psub = getsub(prev)
         if not psup and not psub then
             -- {f} {'}_n => f_n^'
-         -- setchar(current_nucleus,movesub[current_char or getchar(current_nucleus)])
+            fixsupscript(prev,current_nucleus,current_char,new_char)
             local nucleus = getnucleus(parent)
             local sub     = getsub(parent)
-            local sup     = getsup(parent)
             setsup(prev,nucleus)
             setsub(prev,sub)
             local dummy = copy_node(nucleus)
             setchar(dummy,0)
             setnucleus(parent,dummy)
             setsub(parent)
-            if trace_collapsing then
-                report_collapsing("fixing subscript")
-            end
         elseif not psup then
             -- {f} {'}_n => f_n^'
-         -- setchar(current_nucleus,movesub[current_char or getchar(current_nucleus)])
+            fixsupscript(prev,current_nucleus,current_char,new_char)
             local nucleus = getnucleus(parent)
-            local sup     = getsup(parent)
             setsup(prev,nucleus)
             local dummy = copy_node(nucleus)
             setchar(dummy,0)
             setnucleus(parent,dummy)
-            if trace_collapsing then
-                report_collapsing("fixing subscript")
-            end
         end
     end
 end
@@ -1605,7 +1615,9 @@ local function collapsepair(pointer,what,n,parent,nested) -- todo: switch to tur
             local current_nucleus = getnucleus(parent)
             if getid(current_nucleus) == math_char then
                 local current_char = getchar(current_nucleus)
-                if not getsub(parent) and not getsup(parent) then
+                local p_sub = getsub(parent)
+                local p_sup = getsup(parent)
+                if not p_sub and not p_sup then
                     local mathpair = mathpairs[current_char]
                     if mathpair then
                         local next_noad = getnext(parent)
@@ -1642,24 +1654,26 @@ local function collapsepair(pointer,what,n,parent,nested) -- todo: switch to tur
                                             flush_node(next_noad)
                                             collapsepair(pointer,what,n,parent,true)
                                         end
---                                     elseif not nested and movesub[current_char] then
---                                         movesubscript(parent,current_nucleus,current_char)
                                     end
                                 end
                             end
---                         elseif not nested and movesub[current_char] then
---                             movesubscript(parent,current_nucleus,current_char)
                         end
---                     elseif not nested and movesub[current_char] then
---                         movesubscript(parent,current_nucleus,current_char)
                     end
---                 elseif not nested and movesub[current_char] then
---                     movesubscript(parent,current_nucleus,current_char)
+                elseif p_sup then
+                    if getid(p_sup) == math_char then
+                        local current_char = getchar(p_sup)
+                        local new_char = movesub[current_char]
+                        if new_char then
+                            fixsupscript(parent,p_sup,current_char,new_char)
+                        end
+                    end
+                    return
+                end
+                local current_char = getchar(current_nucleus)
+                local new_char = movesub[current_char]
+                if new_char then
+                    movesubscript(parent,current_nucleus,current_char,new_char)
                 end
-local current_char = getchar(current_nucleus)
-if movesub[current_char] then
-    movesubscript(parent,current_nucleus,current_char)
-end
             end
         end
     end
-- 
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