1 files changed, 94 insertions, 0 deletions
diff --git a/tex/context/base/mkxl/math-inc.lmt b/tex/context/base/mkxl/math-inc.lmt
new file mode 100644
index 000000000..7c32adde6
--- /dev/null
+++ b/tex/context/base/mkxl/math-inc.lmt
@@ -0,0 +1,94 @@
+if not modules then modules = { } end modules ['back-inc'] = {
+    version   = 1.001,
+    comment   = "companion to back-exp.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- This is an experiment. If it's really useful then I'll make a more efficient
+-- local export facility.
+
+local tonumber, next = tonumber, next
+local utfbyte, utfchar, utfsplit = utf.byte, utf.char, utf.split
+local match, gsub = string.match, string.gsub
+local nspaces = string.nspaces
+local concat = table.concat
+local xmltext = xml.text
+local undent = buffers.undent
+
+local f_entity = string.formatters["&x%X;"]
+local f_blob   = string.formatters['<?xml version="2.0"?>\n\n<!-- formula %i -->\n\n%s']
+
+local report_tags = logs.reporter("structure","tags")
+
+local all  = nil
+local back = nil
+
+local function unmath(s)
+    local t = utfsplit(s)
+    for i=1,#t do
+        local ti = t[i]
+        local bi = utfbyte(ti)
+        if bi > 0xFFFF then
+            local ch = back[bi]
+            t[i] = ch and utfchar(ch) or f_entity(bi)
+        end
+    end
+    s = concat(t)
+    return s
+end
+
+local function beautify(s)
+    local b = match(s,"^( *)<m:math")
+    local e = match(s,"( *)</m:math>%s*$")
+    if b and e then
+        b = #b
+        e = #e
+        if e > b then
+            s = undent(nspaces[e-b] .. s)
+        elseif e < b then
+            s = undent((gsub(s,"^( *)",nspaces[b-e])))
+        end
+    end
+    return s
+end
+
+local function getblob(n)
+    if all == nil then
+        local name = file.nameonly(tex.jobname)
+        local full = name .. "-export/" .. name .. "-raw.xml"
+        if lfs.isfile(full) then
+            all  = { }
+            back = { }
+            local root  = xml.load(full)
+            for c in xml.collected(root,"formulacontent") do
+                local index = tonumber(c.at.n)
+                local data  = beautify(xmltext(c,"math") or "")
+                if index and data then
+                    all[index] = f_blob(index,data)
+                else
+                    report_tags("no formula content id")
+                end
+            end
+            local it = mathematics.alphabets.regular.it
+            for k, v in next, it.digits    do back[v] = k end
+            for k, v in next, it.ucletters do back[v] = k end
+            for k, v in next, it.lcletters do back[v] = k end
+        else
+            all = false
+        end
+    end
+    if all == false then
+        return ""
+    end
+    return unmath(all[n] or "")
+end
+
+interfaces.implement {
+    name      = "xmlformulatobuffer",
+    arguments = { "integer", "string" },
+    actions   = function(n,target)
+        buffers.assign(target,getblob(n))
+    end
+}