if not modules then modules = { } end modules ['font-con'] = {
    version   = 1.001,
    comment   = "companion to font-ini.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

-- some names of table entries will be changed (no _)

local next, tostring, tonumber, rawget = next, tostring, tonumber, rawget
local format, match, lower, gsub, find = string.format, string.match, string.lower, string.gsub, string.find
local sort, insert, concat = table.sort, table.insert, table.concat
local sortedkeys, sortedhash, serialize, fastcopy = table.sortedkeys, table.sortedhash, table.serialize, table.fastcopy
local derivetable = table.derive
local ioflush = io.flush
local round = math.round
local setmetatable, getmetatable, rawget, rawset = setmetatable, getmetatable, rawget, rawset

local trace_defining  = false  trackers.register("fonts.defining",  function(v) trace_defining = v end)
local trace_scaling   = false  trackers.register("fonts.scaling",   function(v) trace_scaling  = v end)

local report_defining = logs.reporter("fonts","defining")

-- watch out: no negative depths and negative eights permitted in regular fonts

--[[ldx--
<p>Here we only implement a few helper functions.</p>
--ldx]]--

local fonts                  = fonts
local constructors           = fonts.constructors or { }
fonts.constructors           = constructors
local handlers               = fonts.handlers or { } -- can have preloaded tables
fonts.handlers               = handlers

local allocate               = utilities.storage.allocate
local setmetatableindex      = table.setmetatableindex

-- will be directives

constructors.dontembed       = allocate()
constructors.namemode        = "fullpath" -- will be a function

constructors.version         = 1.01
constructors.cache           = containers.define("fonts", "constructors", constructors.version, false)

constructors.privateoffset   = fonts.privateoffsets.textbase or 0xF0000
constructors.cacheintex      = true -- so we see the original table in fonts.font

constructors.addtounicode    = true

constructors.fixprotrusion   = true

-- This might become an interface:

local designsizes           = allocate()
constructors.designsizes    = designsizes
local loadedfonts           = allocate()
constructors.loadedfonts    = loadedfonts

--[[ldx--
<p>We need to normalize the scale factor (in scaled points). This has to
do with the fact that <l n='tex'/> uses a negative multiple of 1000 as
a signal for a font scaled based on the design size.</p>
--ldx]]--

local factors = {
    pt = 65536.0,
    bp = 65781.8,
}

function constructors.setfactor(f)
    constructors.factor = factors[f or 'pt'] or factors.pt
end

constructors.setfactor()

function constructors.scaled(scaledpoints, designsize) -- handles designsize in sp as well
    if scaledpoints < 0 then
        local factor = constructors.factor
        if designsize then
            if designsize > factor then -- or just 1000 / when? mp?
                return (- scaledpoints/1000) * designsize -- sp's
            else
                return (- scaledpoints/1000) * designsize * factor
            end
        else
            return (- scaledpoints/1000) * 10 * factor
        end
    else
        return scaledpoints
    end
end

function constructors.getprivate(tfmdata)
    local properties = tfmdata.properties
    local private = properties.private
    properties.private = private + 1
    return private
end

function constructors.setmathparameter(tfmdata,name,value)
    local m = tfmdata.mathparameters
    local c = tfmdata.MathConstants
    if m then
        m[name] = value
    end
    if c and c ~= m then
        c[name] = value
    end
end

function constructors.getmathparameter(tfmdata,name)
    local p = tfmdata.mathparameters or tfmdata.MathConstants
    if p then
        return p[name]
    end
end

--[[ldx--
<p>Beware, the boundingbox is passed as reference so we may not overwrite it
in the process; numbers are of course copies. Here 65536 equals 1pt. (Due to
excessive memory usage in CJK fonts, we no longer pass the boundingbox.)</p>
--ldx]]--

-- The scaler is only used for otf and afm and virtual fonts. If a virtual font has italic
-- correction make sure to set the hasitalics flag. Some more flags will be added in the
-- future.

--[[ldx--
<p>The reason why the scaler was originally split, is that for a while we experimented
with a helper function. However, in practice the <l n='api'/> calls are too slow to
make this profitable and the <l n='lua'/> based variant was just faster. A days
wasted day but an experience richer.</p>
--ldx]]--

function constructors.cleanuptable(tfmdata)
    -- This no longer makes sense because the addition of font.getcopy and its
    -- possible usage in generic implicates that we need to return the whole
    -- lot now.
end

-- experimental, sharing kerns (unscaled and scaled) saves memory
-- local sharedkerns, basekerns = constructors.check_base_kerns(tfmdata)
-- loop over descriptions (afm and otf have descriptions, tfm not)
-- there is no need (yet) to assign a value to chr.tonunicode

-- constructors.prepare_base_kerns(tfmdata) -- optimalization

-- we have target.name=metricfile and target.fullname=RealName and target.filename=diskfilename
-- when collapsing fonts, luatex looks as both target.name and target.fullname as ttc files
-- can have multiple subfonts

function constructors.calculatescale(tfmdata,scaledpoints)
    local parameters = tfmdata.parameters
    if scaledpoints < 0 then
        scaledpoints = (- scaledpoints/1000) * (tfmdata.designsize or parameters.designsize) -- already in sp
    end
    return scaledpoints, scaledpoints / (parameters.units or 1000) -- delta
end

local unscaled = {
    ScriptPercentScaleDown          = true,
    ScriptScriptPercentScaleDown    = true,
    RadicalDegreeBottomRaisePercent = true,
    NoLimitSupFactor                = true,
    NoLimitSubFactor                = true,
}

function constructors.assignmathparameters(target,original) -- simple variant, not used in context
    -- when a tfm file is loaded, it has already been scaled
    -- and it never enters the scaled so this is otf only and
    -- even then we do some extra in the context math plugins
    local mathparameters = original.mathparameters
    if mathparameters and next(mathparameters) then
        local targetparameters     = target.parameters
        local targetproperties     = target.properties
        local targetmathparameters = { }
        local factor               = targetproperties.math_is_scaled and 1 or targetparameters.factor
        for name, value in next, mathparameters do
            if unscaled[name] then
                targetmathparameters[name] = value
            else
                targetmathparameters[name] = value * factor
            end
        end
        if not targetmathparameters.FractionDelimiterSize then
            targetmathparameters.FractionDelimiterSize = 1.01 * targetparameters.size
        end
        if not mathparameters.FractionDelimiterDisplayStyleSize then
            targetmathparameters.FractionDelimiterDisplayStyleSize = 2.40 * targetparameters.size
        end
        target.mathparameters = targetmathparameters
    end
end

function constructors.beforecopyingcharacters(target,original)
    -- can be used for additional tweaking
end

function constructors.aftercopyingcharacters(target,original)
    -- can be used for additional tweaking
end

-- It's probably ok to hash just the indices because there is not that much
-- chance that one will shift slots and leave the others unset then. Anyway,
-- there is of course some overhead here, but it might as well get compensated
-- by less time spent on including the font resource twice. For the moment
-- we default to false, so a macro package has to enable it explicitly. In
-- LuaTeX the fullname is used to identify a font as being unique.

constructors.sharefonts     = false
constructors.nofsharedfonts = 0
local sharednames           = { }

function constructors.trytosharefont(target,tfmdata)
    if constructors.sharefonts then -- not robust !
        local characters = target.characters
        local n = 1
        local t = { target.psname }
        local u = sortedkeys(characters)
        for i=1,#u do
            local k = u[i]
            n = n + 1 ; t[n] = k
            n = n + 1 ; t[n] = characters[k].index or k
        end
        local h = md5.HEX(concat(t," "))
        local s = sharednames[h]
        if s then
            if trace_defining then
                report_defining("font %a uses backend resources of font %a",target.fullname,s)
            end
            target.fullname = s
            constructors.nofsharedfonts = constructors.nofsharedfonts + 1
            target.properties.sharedwith = s
        else
            sharednames[h] = target.fullname
        end
    end
end

-- function constructors.enhanceparameters(parameters)
--     local xheight = parameters.x_height
--     local quad    = parameters.quad
--     local space   = parameters.space
--     local stretch = parameters.space_stretch
--     local shrink  = parameters.space_shrink
--     local extra   = parameters.extra_space
--     local slant   = parameters.slant
--     -- synonyms
--     parameters.xheight       = xheight
--     parameters.spacestretch  = stretch
--     parameters.spaceshrink   = shrink
--     parameters.extraspace    = extra
--     parameters.em            = quad
--     parameters.ex            = xheight
--     parameters.slantperpoint = slant
--     parameters.spacing = {
--         width   = space,
--         stretch = stretch,
--         shrink  = shrink,
--         extra   = extra,
--     }
-- end

local synonyms = {
    exheight      = "x_height",
    xheight       = "x_height",
    ex            = "x_height",
    emwidth       = "quad",
    em            = "quad",
    spacestretch  = "space_stretch",
    stretch       = "space_stretch",
    spaceshrink   = "space_shrink",
    shrink        = "space_shrink",
    extraspace    = "extra_space",
    xspace        = "extra_space",
    slantperpoint = "slant",
}

function constructors.enhanceparameters(parameters)
    local mt = getmetatable(parameters)
    local getter = function(t,k)
        if not k then
            return nil
        end
        local s = synonyms[k]
        if s then
            return rawget(t,s) or (mt and mt[s]) or nil
        end
        if k == "spacing" then
            return {
                width   = t.space,
                stretch = t.space_stretch,
                shrink  = t.space_shrink,
                extra   = t.extra_space,
            }
        end
        return mt and mt[k] or nil
    end
    local setter = function(t,k,v)
        if not k then
            return 0
        end
        local s = synonyms[k]
        if s then
            rawset(t,s,v)
        elseif k == "spacing" then
            if type(v) == "table" then
                rawset(t,"space",v.width or 0)
                rawset(t,"space_stretch",v.stretch or 0)
                rawset(t,"space_shrink",v.shrink or 0)
                rawset(t,"extra_space",v.extra or 0)
            end
        else
            rawset(t,k,v)
        end
    end
    setmetatable(parameters, {
        __index    = getter,
        __newindex = setter,
    })
end

local function mathkerns(v,vdelta)
    local k = { }
    for i=1,#v do
        local entry  = v[i]
        local height = entry.height
        local kern   = entry.kern
        k[i] = {
            height = height and vdelta*height or 0,
            kern   = kern   and vdelta*kern   or 0,
        }
    end
    return k
end

local psfake = 0

local function fixedpsname(psname,fallback)
    local usedname = psname
    if psname and psname ~= "" then
        if find(psname," ",1,true) then
            usedname = gsub(psname,"[%s]+","-")
        else
            -- we assume that the name is sane enough (we might sanitize completely some day)
        end
    elseif not fallback or fallback == "" then
        psfake = psfake + 1
        psname = "fakename-" .. psfake
    else
        -- filenames can be a mess so we do a drastic cleanup
        psname   = fallback
        usedname = gsub(psname,"[^a-zA-Z0-9]+","-")
    end
    return usedname, psname ~= usedname
end

function constructors.scale(tfmdata,specification)
    local target         = { } -- the new table
    --
    if tonumber(specification) then
        specification    = { size = specification }
    end
    target.specification = specification
    --
    local scaledpoints   = specification.size
    local relativeid     = specification.relativeid
    --
    local properties     = tfmdata.properties     or { }
    local goodies        = tfmdata.goodies        or { }
    local resources      = tfmdata.resources      or { }
    local descriptions   = tfmdata.descriptions   or { } -- bad news if empty
    local characters     = tfmdata.characters     or { } -- bad news if empty
    local changed        = tfmdata.changed        or { } -- for base mode
    local shared         = tfmdata.shared         or { }
    local parameters     = tfmdata.parameters     or { }
    local mathparameters = tfmdata.mathparameters or { }
    --
    local targetcharacters     = { }
    local targetdescriptions   = derivetable(descriptions)
    local targetparameters     = derivetable(parameters)
    local targetproperties     = derivetable(properties)
    local targetgoodies        = goodies                        -- we need to loop so no metatable
    target.characters          = targetcharacters
    target.descriptions        = targetdescriptions
    target.parameters          = targetparameters
 -- target.mathparameters      = targetmathparameters           -- happens elsewhere
    target.properties          = targetproperties
    target.goodies             = targetgoodies
    target.shared              = shared
    target.resources           = resources
    target.unscaled            = tfmdata                        -- the original unscaled one
    --
    -- specification.mathsize : 1=text 2=script 3=scriptscript
    -- specification.textsize : natural (text)size
    -- parameters.mathsize    : 1=text 2=script 3=scriptscript >1000 enforced size (feature value other than yes)
    --
    local mathsize    = tonumber(specification.mathsize) or 0
    local textsize    = tonumber(specification.textsize) or scaledpoints
    local forcedsize  = tonumber(parameters.mathsize   ) or 0 -- can be set by the feature "mathsize"
    local extrafactor = tonumber(specification.factor  ) or 1
    if (mathsize == 2 or forcedsize == 2) and parameters.scriptpercentage then
        scaledpoints = parameters.scriptpercentage * textsize / 100
    elseif (mathsize == 3 or forcedsize == 3) and parameters.scriptscriptpercentage then
        scaledpoints = parameters.scriptscriptpercentage * textsize / 100
    elseif forcedsize > 1000 then -- safeguard
        scaledpoints = forcedsize
    else
        -- in context x and xx also use mathsize
    end
    targetparameters.mathsize    = mathsize    -- context specific
    targetparameters.textsize    = textsize    -- context specific
    targetparameters.forcedsize  = forcedsize  -- context specific
    targetparameters.extrafactor = extrafactor -- context specific
    --
    local addtounicode  = constructors.addtounicode
    --
    local tounicode     = fonts.mappings.tounicode
    local unknowncode   = tounicode(0xFFFD)
    --
    local defaultwidth  = resources.defaultwidth  or 0
    local defaultheight = resources.defaultheight or 0
    local defaultdepth  = resources.defaultdepth or 0
    local units         = parameters.units or 1000
    --
    -- boundary keys are no longer needed as we now have a string 'right_boundary'
    -- that can be used in relevant tables (kerns and ligatures) ... not that I ever
    -- used them
    --
 -- boundarychar_label = 0,     -- not needed
 -- boundarychar       = 65536, -- there is now a string 'right_boundary'
 -- false_boundarychar = 65536, -- produces invalid tfm in luatex
    --
    targetproperties.language   = properties.language or "dflt" -- inherited
    targetproperties.script     = properties.script   or "dflt" -- inherited
    targetproperties.mode       = properties.mode     or "base" -- inherited
    targetproperties.method     = properties.method
    --
    local askedscaledpoints   = scaledpoints
    local scaledpoints, delta = constructors.calculatescale(tfmdata,scaledpoints,nil,specification) -- no shortcut, dan be redefined
    --
    local hdelta         = delta
    local vdelta         = delta
    --
    target.designsize    = parameters.designsize -- not really needed so it might become obsolete
    target.units         = units
    target.units_per_em  = units                 -- just a trigger for the backend
    --
    local direction      = properties.direction or tfmdata.direction or 0 -- pointless, as we don't use omf fonts at all
    target.direction     = direction
    properties.direction = direction
    --
    target.size          = scaledpoints
    --
    target.encodingbytes = properties.encodingbytes or 1
    target.subfont       = properties.subfont
    target.embedding     = properties.embedding or "subset"
    target.tounicode     = 1
    target.cidinfo       = properties.cidinfo
    target.format        = properties.format
    target.cache         = constructors.cacheintex and "yes" or "renew"
    --
    local fontname = properties.fontname or tfmdata.fontname
    local fullname = properties.fullname or tfmdata.fullname
    local filename = properties.filename or tfmdata.filename
    local psname   = properties.psname   or tfmdata.psname
    local name     = properties.name     or tfmdata.name
    --
    -- The psname used in pdf file as well as for selecting subfont in ttc although
    -- we don't need that subfont look up here (mapfile stuff).
    --
    local psname, psfixed = fixedpsname(psname,fontname or fullname or file.nameonly(filename))
    --
    target.fontname = fontname
    target.fullname = fullname
    target.filename = filename
    target.psname   = psname
    target.name     = name
    --
    properties.fontname = fontname
    properties.fullname = fullname
    properties.filename = filename
    properties.psname   = psname
    properties.name     = name
    -- expansion (hz)
    local expansion = parameters.expansion
    if expansion then
        target.stretch = expansion.stretch
        target.shrink  = expansion.shrink
        target.step    = expansion.step
    end
    -- slanting
    local slantfactor = parameters.slantfactor or 0
    if slantfactor ~= 0 then
        target.slant = slantfactor * 1000
    else
        target.slant = 0
    end
    -- widening
    local extendfactor = parameters.extendfactor or 0
    if extendfactor ~= 0 and extendfactor ~= 1 then
        hdelta = hdelta * extendfactor
        target.extend = extendfactor * 1000
    else
        target.extend = 1000 -- extent ?
    end
    -- squeezing
    local squeezefactor = parameters.squeezefactor or 0
    if squeezefactor ~= 0 and squeezefactor ~= 1 then
        vdelta = vdelta * squeezefactor
        target.squeeze = squeezefactor * 1000
    else
        target.squeeze = 1000 -- extent ?
    end
    -- effects
    local mode = parameters.mode or 0
    if mode ~= 0 then
        target.mode = mode
    end
    local width = parameters.width or 0
    if width ~= 0 then
        target.width = width * delta * 1000 / 655360
    end
    --
    targetparameters.factor       = delta
    targetparameters.hfactor      = hdelta
    targetparameters.vfactor      = vdelta
    targetparameters.size         = scaledpoints
    targetparameters.units        = units
    targetparameters.scaledpoints = askedscaledpoints
    targetparameters.mode         = mode
    targetparameters.width        = width
    --
    local isvirtual        = properties.virtualized or tfmdata.type == "virtual"
    local hasquality       = parameters.expansion or parameters.protrusion
    local hasitalics       = properties.hasitalics
    local autoitalicamount = properties.autoitalicamount
    local stackmath        = not properties.nostackmath
    local haskerns         = properties.haskerns     or properties.mode == "base" -- we can have afm in node mode
    local hasligatures     = properties.hasligatures or properties.mode == "base" -- we can have afm in node mode
    local realdimensions   = properties.realdimensions
    local writingmode      = properties.writingmode or "horizontal"
    local identity         = properties.identity or "horizontal"
    --
    local vfonts = target.fonts
    if vfonts and #vfonts > 0 then
        target.fonts = fastcopy(vfonts) -- maybe we virtualize more afterwards
    elseif isvirtual then
        target.fonts = { { id = 0 } } -- catch error
    end
    --
    if changed and not next(changed) then
        changed = false
    end
    --
    target.type        = isvirtual and "virtual" or "real"
    target.writingmode = writingmode == "vertical" and "vertical" or "horizontal"
    target.identity    = identity == "vertical" and "vertical" or "horizontal"
    --
    target.postprocessors = tfmdata.postprocessors
    --
    local targetslant         = (parameters.slant         or parameters[1] or 0) * factors.pt -- per point
    local targetspace         = (parameters.space         or parameters[2] or 0) * hdelta
    local targetspace_stretch = (parameters.space_stretch or parameters[3] or 0) * hdelta
    local targetspace_shrink  = (parameters.space_shrink  or parameters[4] or 0) * hdelta
    local targetx_height      = (parameters.x_height      or parameters[5] or 0) * vdelta
    local targetquad          = (parameters.quad          or parameters[6] or 0) * hdelta
    local targetextra_space   = (parameters.extra_space   or parameters[7] or 0) * hdelta
    --
    targetparameters.slant         = targetslant -- slantperpoint
    targetparameters.space         = targetspace
    targetparameters.space_stretch = targetspace_stretch
    targetparameters.space_shrink  = targetspace_shrink
    targetparameters.x_height      = targetx_height
    targetparameters.quad          = targetquad
    targetparameters.extra_space   = targetextra_space
    --
    local ascender = parameters.ascender
    if ascender then
        targetparameters.ascender  = delta * ascender
    end
    local descender = parameters.descender
    if descender then
        targetparameters.descender = delta * descender
    end
    --
    constructors.enhanceparameters(targetparameters) -- official copies for us, now virtual
    --
    -- I need to fix this in luatex ... get rid of quad there so that we can omit this here.
    --
    local protrusionfactor = constructors.fixprotrusion and ((targetquad ~= 0 and 1000/targetquad) or 1) or 1
    --
    local scaledwidth      = defaultwidth  * hdelta
    local scaledheight     = defaultheight * vdelta
    local scaleddepth      = defaultdepth  * vdelta
    --
    local hasmath = (properties.hasmath or next(mathparameters)) and true
    --
    if hasmath then
        constructors.assignmathparameters(target,tfmdata) -- does scaling and whatever is needed
        properties.hasmath      = true
        target.nomath           = false
        target.MathConstants    = target.mathparameters
    else
        properties.hasmath      = false
        target.nomath           = true
        target.mathparameters   = nil -- nop
    end
    --
    -- Here we support some context specific trickery (this might move to a plugin). During the
    -- transition to opentype the engine had troubles with italics so we had some additional code
    -- for fixing that. In node mode (text) we don't care much if italics gets passed because
    -- the engine does nothign with them then.
    --
    if hasmath then
        local mathitalics = properties.mathitalics
        if mathitalics == false then
            if trace_defining then
                report_defining("%s italics %s for font %a, fullname %a, filename %a","math",hasitalics and "ignored" or "disabled",name,fullname,filename)
            end
            hasitalics       = false
            autoitalicamount = false
        end
    else
        local textitalics = properties.textitalics
        if textitalics == false then
            if trace_defining then
                report_defining("%s italics %s for font %a, fullname %a, filename %a","text",hasitalics and "ignored" or "disabled",name,fullname,filename)
            end
            hasitalics       = false
            autoitalicamount = false
        end
    end
    --
    -- end of context specific trickery
    --
    if trace_defining then
        report_defining("defining tfm, name %a, fullname %a, filename %a, %spsname %a, hscale %a, vscale %a, math %a, italics %a",
            name,fullname,filename,psfixed and "(fixed) " or "",psname,hdelta,vdelta,
            hasmath and "enabled" or "disabled",hasitalics and "enabled" or "disabled")
    end
    --
    constructors.beforecopyingcharacters(target,tfmdata)
    --
    local sharedkerns = { }
    --
    -- we can have a dumb mode (basemode without math etc) that skips most
    --
    for unicode, character in next, characters do
        local chr, description, index
        if changed then
            local c = changed[unicode]
            if c and c ~= unicode then
                if c then
                    description = descriptions[c] or descriptions[unicode] or character
                    character   = characters[c] or character
                    index       = description.index or c
                else
                    description = descriptions[unicode] or character
                    index       = description.index or unicode
                end
            else
                description = descriptions[unicode] or character
                index       = description.index or unicode
            end
        else
            description = descriptions[unicode] or character
            index       = description.index or unicode
        end
        local width     = description.width
        local height    = description.height
        local depth     = description.depth
        local isunicode = description.unicode
        if realdimensions then
            -- this is mostly for checking issues
            if not height or height == 0 then
                local bb = description.boundingbox
                local ht =  bb[4]
                if ht ~= 0 then
                    height = ht
                end
                if not depth or depth == 0 then
                    local dp = -bb[2]
                    if dp ~= 0 then
                        depth = dp
                    end
                end
            elseif not depth or depth == 0 then
                local dp = -description.boundingbox[2]
                if dp ~= 0 then
                    depth = dp
                end
            end
        end
        if width  then width  = hdelta*width  else width  = scaledwidth  end
        if height then height = vdelta*height else height = scaledheight end
    --  if depth  then depth  = vdelta*depth  else depth  = scaleddepth  end
        if depth and depth ~= 0 then
            depth = delta*depth
            if isunicode then
                chr = {
                    index   = index,
                    height  = height,
                    depth   = depth,
                    width   = width,
                    unicode = isunicode,
                }
            else
                chr = {
                    index  = index,
                    height = height,
                    depth  = depth,
                    width  = width,
                }
            end
        else
            if isunicode then
                chr = {
                    index   = index,
                    height  = height,
                    width   = width,
                    unicode = isunicode,
                }
            else
                chr = {
                    index  = index,
                    height = height,
                    width  = width,
                }
            end
        end
        if addtounicode then
            chr.tounicode = isunicode and tounicode(isunicode) or unknowncode
        end
        if hasquality then
            -- we could move these calculations elsewhere (saves calculations)
            local ve = character.expansion_factor
            if ve then
                chr.expansion_factor = ve*1000 -- expansionfactor, hm, can happen elsewhere
            end
            local vl = character.left_protruding
            if vl then
                chr.left_protruding  = protrusionfactor*width*vl
            end
            local vr = character.right_protruding
            if vr then
                chr.right_protruding  = protrusionfactor*width*vr
            end
        end
        --
        if hasmath then
            --
            -- todo, just operate on descriptions.math
            local vn = character.next
            if vn then
                chr.next = vn
            else
                local vv = character.vert_variants
                if vv then
                    local t = { }
                    for i=1,#vv do
                        local vvi = vv[i]
                        local s = vvi["start"]   or 0
                        local e = vvi["end"]     or 0
                        local a = vvi["advance"] or 0
                        t[i] = { -- zero check nicer for 5.3
                            ["start"]    = s == 0 and 0 or s * vdelta,
                            ["end"]      = e == 0 and 0 or e * vdelta,
                            ["advance"]  = a == 0 and 0 or a * vdelta,
                            ["extender"] = vvi["extender"],
                            ["glyph"]    = vvi["glyph"],
                        }
                    end
                    chr.vert_variants = t
                else
                    local hv = character.horiz_variants
                    if hv then
                        local t = { }
                        for i=1,#hv do
                            local hvi = hv[i]
                            local s = hvi["start"]   or 0
                            local e = hvi["end"]     or 0
                            local a = hvi["advance"] or 0
                            t[i] = { -- zero check nicer for 5.3
                                ["start"]    = s == 0 and 0 or s * hdelta,
                                ["end"]      = e == 0 and 0 or e * hdelta,
                                ["advance"]  = a == 0 and 0 or a * hdelta,
                                ["extender"] = hvi["extender"],
                                ["glyph"]    = hvi["glyph"],
                            }
                        end
                        chr.horiz_variants = t
                    end
                end
                -- todo also check mathitalics (or that one can go away)
            end
            local vi = character.vert_italic
            if vi and vi ~= 0 then
                chr.vert_italic = vi*hdelta
            end
            local va = character.accent
            if va then
                chr.top_accent = vdelta*va
            end
            if stackmath then
                local mk = character.mathkerns
                if mk then
                    local tr = mk.topright
                    local tl = mk.topleft
                    local br = mk.bottomright
                    local bl = mk.bottomleft
                    chr.mathkern = { -- singular -> should be patched in luatex !
                        top_right    = tr and mathkerns(tr,vdelta) or nil,
                        top_left     = tl and mathkerns(tl,vdelta) or nil,
                        bottom_right = br and mathkerns(br,vdelta) or nil,
                        bottom_left  = bl and mathkerns(bl,vdelta) or nil,
                    }
                end
            end
            if hasitalics then
                local vi = character.italic
                if vi and vi ~= 0 then
                    chr.italic = vi*hdelta
                end
            end
        elseif autoitalicamount then -- itlc feature
            local vi = description.italic
            if not vi then
                local bb = description.boundingbox
                if bb then
                    local vi = bb[3] - description.width + autoitalicamount
                    if vi > 0 then -- < 0 indicates no overshoot or a very small auto italic
                        chr.italic = vi*hdelta
                    end
                else
                 -- report_defining("no boundingbox for character %C in font %a, fullname %a, filename %a",unicode,name,fullname,filename)
                end
            elseif vi ~= 0 then
                chr.italic = vi*hdelta
            end
        elseif hasitalics then -- unlikely
            local vi = character.italic
            if vi and vi ~= 0 then
                chr.italic = vi*hdelta
            end
        end
        if haskerns then
            local vk = character.kerns
            if vk then
                local s = sharedkerns[vk]
                if not s then
                    s = { }
                    for k,v in next, vk do s[k] = v*hdelta end
                    sharedkerns[vk] = s
                end
                chr.kerns = s
            end
        end
        if hasligatures then
            local vl = character.ligatures
            if vl then
                if true then
                    chr.ligatures = vl -- shared
                else
                    local tt = { }
                    for i, l in next, vl do
                        tt[i] = l
                    end
                    chr.ligatures = tt
                end
            end
        end
        if isvirtual then
            local vc = character.commands
            if vc then
                -- we assume non scaled commands here
                -- tricky .. we need to scale pseudo math glyphs too
                -- which is why we deal with rules too
                local ok = false
                for i=1,#vc do
                    local key = vc[i][1]
                    if key == "right" or key == "down" or key == "rule" then
                        ok = true
                        break
                    end
                end
                if ok then
                    local tt = { }
                    for i=1,#vc do
                        local ivc = vc[i]
                        local key = ivc[1]
                        if key == "right" then
                            tt[i] = { key, ivc[2]*hdelta }
                        elseif key == "down" then
                            tt[i] = { key, ivc[2]*vdelta }
                        elseif key == "rule" then
                            tt[i] = { key, ivc[2]*vdelta, ivc[3]*hdelta }
                        else -- not comment
                            tt[i] = ivc -- shared since in cache and untouched
                        end
                    end
                    chr.commands = tt
                else
                    chr.commands = vc
                end
             -- chr.index = nil
            end
        end
        targetcharacters[unicode] = chr
    end
    --
    properties.setitalics = hasitalics -- for postprocessing
    --
    constructors.aftercopyingcharacters(target,tfmdata)
    --
    constructors.trytosharefont(target,tfmdata)
    --
    -- catch inconsistencies
    --
    local vfonts = target.fonts
    if isvirtual or target.type == "virtual" or properties.virtualized then
        properties.virtualized = true
        target.type = "virtual"
        if not vfonts or #vfonts == 0 then
            target.fonts = { { id = 0 } }
        end
    elseif vfonts then
        properties.virtualized = true
        target.type = "virtual"
        if #vfonts == 0 then
            target.fonts = { { id = 0 } }
        end
    end
    --
    return target
end

function constructors.finalize(tfmdata)
    if tfmdata.properties and tfmdata.properties.finalized then
        return
    end
    --
    if not tfmdata.characters then
        return nil
    end
    --
    if not tfmdata.goodies then
        tfmdata.goodies = { } -- context specific
    end
    --
    local parameters = tfmdata.parameters
    if not parameters then
        return nil
    end
    --
    if not parameters.expansion then
        parameters.expansion = {
            stretch = tfmdata.stretch or 0,
            shrink  = tfmdata.shrink  or 0,
            step    = tfmdata.step    or 0,
        }
    end
    --
    if not parameters.size then
        parameters.size = tfmdata.size
    end
    --
    if not parameters.mode then
        parameters.mode = 0
    end
    --
    if not parameters.width then
        parameters.width = 0
    end
    --
    if not parameters.slantfactor then
        parameters.slantfactor = (tfmdata.slant or 0)/1000
    end
    --
    if not parameters.extendfactor then
        parameters.extendfactor = (tfmdata.extend or 1000)/1000
    end
    --
    if not parameters.squeezefactor then
        parameters.squeezefactor = (tfmdata.squeeze or 1000)/1000
    end
    --
    local designsize = parameters.designsize
    if designsize then
        parameters.minsize = tfmdata.minsize or designsize
        parameters.maxsize = tfmdata.maxsize or designsize
    else
        designsize = factors.pt * 10
        parameters.designsize = designsize
        parameters.minsize    = designsize
        parameters.maxsize    = designsize
    end
    parameters.minsize = tfmdata.minsize or parameters.designsize
    parameters.maxsize = tfmdata.maxsize or parameters.designsize
    --
    if not parameters.units then
        parameters.units = tfmdata.units or tfmdata.units_per_em or 1000
    end
    --
    if not tfmdata.descriptions then
        local descriptions = { } -- yes or no
        setmetatableindex(descriptions, function(t,k) local v = { } t[k] = v return v end)
        tfmdata.descriptions = descriptions
    end
    --
    local properties = tfmdata.properties
    if not properties then
        properties = { }
        tfmdata.properties = properties
    end
    --
    if not properties.virtualized then
        properties.virtualized = tfmdata.type == "virtual"
    end
    --
    properties.fontname      = properties.fontname or tfmdata.fontname
    properties.filename      = properties.filename or tfmdata.filename
    properties.fullname      = properties.fullname or tfmdata.fullname
    properties.name          = properties.name     or tfmdata.name
    properties.psname        = properties.psname   or tfmdata.psname
    --
    properties.encodingbytes = tfmdata.encodingbytes or 1
    properties.subfont       = tfmdata.subfont       or nil
    properties.embedding     = tfmdata.embedding     or "subset"
    properties.tounicode     = tfmdata.tounicode     or 1
    properties.cidinfo       = tfmdata.cidinfo       or nil
    properties.format        = tfmdata.format        or "type1"
    properties.direction     = tfmdata.direction     or 0
    properties.writingmode   = tfmdata.writingmode   or "horizontal"
    properties.identity      = tfmdata.identity      or "horizontal"
    properties.usedbitmap    = tfmdata.usedbitmap
    --
    if not tfmdata.resources then
        tfmdata.resources = { }
    end
    if not tfmdata.shared then
        tfmdata.shared = { }
    end
    --
    -- tfmdata.fonts
    -- tfmdata.unscaled
    --
    if not properties.hasmath then
        properties.hasmath = not tfmdata.nomath
    end
    --
    tfmdata.MathConstants    = nil
    tfmdata.postprocessors   = nil
    --
    tfmdata.fontname         = nil
    tfmdata.filename         = nil
    tfmdata.fullname         = nil
    tfmdata.name             = nil -- most tricky part
    tfmdata.psname           = nil
    --
    tfmdata.encodingbytes    = nil
    tfmdata.subfont          = nil
    tfmdata.embedding        = nil
    tfmdata.tounicode        = nil
    tfmdata.cidinfo          = nil
    tfmdata.format           = nil
    tfmdata.direction        = nil
    tfmdata.type             = nil
    tfmdata.nomath           = nil
    tfmdata.designsize       = nil
    --
    tfmdata.size             = nil
    tfmdata.stretch          = nil
    tfmdata.shrink           = nil
    tfmdata.step             = nil
    tfmdata.slant            = nil
    tfmdata.extend           = nil
    tfmdata.squeeze          = nil
    tfmdata.mode             = nil
    tfmdata.width            = nil
    tfmdata.units            = nil
    tfmdata.units_per_em     = nil
    --
    tfmdata.cache            = nil
    --
    properties.finalized     = true
    --
    return tfmdata
end

--[[ldx--
<p>A unique hash value is generated by:</p>
--ldx]]--

local hashmethods        = { }
constructors.hashmethods = hashmethods

function constructors.hashfeatures(specification) -- will be overloaded
    local features = specification.features
    if features then
        local t, n = { }, 0
        for category, list in sortedhash(features) do
            if next(list) then
                local hasher = hashmethods[category]
                if hasher then
                    local hash = hasher(list)
                    if hash then
                        n = n + 1
                        t[n] = category .. ":" .. hash
                    end
                end
            end
        end
        if n > 0 then
            return concat(t," & ")
        end
    end
    return "unknown"
end

hashmethods.normal = function(list)
    local s = { }
    local n = 0
    for k, v in next, list do
        if not k then
            -- no need to add to hash
        elseif k == "number" or k == "features" then
            -- no need to add to hash (maybe we need a skip list)
        else
            n = n + 1
            if type(v) == "table" then
                -- table.sequenced
                local t = { }
                local m = 0
                for k, v in next, v do
                    m = m + 1
                    t[m] = k .. '=' .. tostring(v)
                end
                sort(t)
                s[n] = k .. '={' .. concat(t,",") .. "}"
            else
                s[n] = k .. '=' .. tostring(v)
            end
        end
    end
    if n > 0 then
        sort(s)
        return concat(s,"+")
    end
end

--[[ldx--
<p>In principle we can share tfm tables when we are in need for a font, but then
we need to define a font switch as an id/attr switch which is no fun, so in that
case users can best use dynamic features ... so, we will not use that speedup. Okay,
when we get rid of base mode we can optimize even further by sharing, but then we
loose our testcases for <l n='luatex'/>.</p>
--ldx]]--

function constructors.hashinstance(specification,force)
    local hash      = specification.hash
    local size      = specification.size
    local fallbacks = specification.fallbacks
    if force or not hash then
        hash = constructors.hashfeatures(specification)
        specification.hash = hash
    end
    if size < 1000 and designsizes[hash] then
        size = round(constructors.scaled(size,designsizes[hash]))
    else
        size = round(size)
    end
    specification.size = size
    if fallbacks then
        return hash .. ' @ ' .. size .. ' @ ' .. fallbacks
    else
        return hash .. ' @ ' .. size
    end
end

function constructors.setname(tfmdata,specification) -- todo: get specification from tfmdata
    if constructors.namemode == "specification" then
        -- not to be used in context !
        local specname = specification.specification
        if specname then
            tfmdata.properties.name = specname
            if trace_defining then
                report_otf("overloaded fontname %a",specname)
            end
        end
    end
end

function constructors.checkedfilename(data)
    local foundfilename = data.foundfilename
    if not foundfilename then
        local askedfilename = data.filename or ""
        if askedfilename ~= "" then
            askedfilename = resolvers.resolve(askedfilename) -- no shortcut
            foundfilename = resolvers.findbinfile(askedfilename,"") or ""
            if foundfilename == "" then
                report_defining("source file %a is not found",askedfilename)
                foundfilename = resolvers.findbinfile(file.basename(askedfilename),"") or ""
                if foundfilename ~= "" then
                    report_defining("using source file %a due to cache mismatch",foundfilename)
                end
            end
        end
        data.foundfilename = foundfilename
    end
    return foundfilename
end

local formats = allocate()
fonts.formats = formats

setmetatableindex(formats, function(t,k)
    local l = lower(k)
    if rawget(t,k) then
        t[k] = l
        return l
    end
    return rawget(t,file.suffix(l))
end)

do

    local function setindeed(mode,source,target,group,name,position)
        local action = source[mode]
        if not action then
            return
        end
        local t = target[mode]
        if not t then
            report_defining("fatal error in setting feature %a, group %a, mode %a",name,group,mode)
            os.exit()
        elseif position then
            -- todo: remove existing
            insert(t, position, { name = name, action = action })
        else
            for i=1,#t do
                local ti = t[i]
                if ti.name == name then
                    ti.action = action
                    return
                end
            end
            insert(t, { name = name, action = action })
        end
    end

    local function set(group,name,target,source)
        target = target[group]
        if not target then
            report_defining("fatal target error in setting feature %a, group %a",name,group)
            os.exit()
        end
        local source = source[group]
        if not source then
            report_defining("fatal source error in setting feature %a, group %a",name,group)
            os.exit()
        end
        local position = source.position
        setindeed("node",source,target,group,name,position)
        setindeed("base",source,target,group,name,position)
        setindeed("plug",source,target,group,name,position)
    end

    local function register(where,specification)
        local name = specification.name
        if name and name ~= "" then
            local default      = specification.default
            local description  = specification.description
            local initializers = specification.initializers
            local processors   = specification.processors
            local manipulators = specification.manipulators
            local modechecker  = specification.modechecker
            if default then
                where.defaults[name] = default
            end
            if description and description ~= "" then
                where.descriptions[name] = description
            end
            if initializers then
                set('initializers',name,where,specification)
            end
            if processors then
                set('processors',  name,where,specification)
            end
            if manipulators then
                set('manipulators',name,where,specification)
            end
            if modechecker then
               where.modechecker = modechecker
            end
        end
    end

    constructors.registerfeature = register

    function constructors.getfeatureaction(what,where,mode,name)
        what = handlers[what].features
        if what then
            where = what[where]
            if where then
                mode = where[mode]
                if mode then
                    for i=1,#mode do
                        local m = mode[i]
                        if m.name == name then
                            return m.action
                        end
                    end
                end
            end
        end
    end

    local newfeatures        = { }
    constructors.newfeatures = newfeatures -- downward compatible
    constructors.features    = newfeatures

    local function setnewfeatures(what)
        local handler  = handlers[what]
        local features = handler.features
        if not features then
            local tables     = handler.tables     -- can be preloaded
            local statistics = handler.statistics -- can be preloaded
            features = allocate {
                defaults     = { },
                descriptions = tables and tables.features or { },
                used         = statistics and statistics.usedfeatures or { },
                initializers = { base = { }, node = { }, plug = { } },
                processors   = { base = { }, node = { }, plug = { } },
                manipulators = { base = { }, node = { }, plug = { } },
            }
            features.register = function(specification) return register(features,specification) end
            handler.features = features -- will also become hidden
        end
        return features
    end

    setmetatable(newfeatures, {
        __call  = function(t,k) local v = t[k] return v end,
        __index = function(t,k) local v = setnewfeatures(k) t[k] = v return v end,
    })

end

do

    local newhandler        = { }
    constructors.handlers   = newhandler -- downward compatible
    constructors.newhandler = newhandler

    local function setnewhandler(what) -- could be a metatable newindex
        local handler = handlers[what]
        if not handler then
            handler = { }
            handlers[what] = handler
        end
        return handler
    end

    setmetatable(newhandler, {
        __call  = function(t,k) local v = t[k] return v end,
        __index = function(t,k) local v = setnewhandler(k) t[k] = v return v end,
    })

end

do
    -- a pitty that we need to be generic as we have nicer mechanisms for this ...

    local newenhancer        = { }
    constructors.enhancers   = newenhancer
    constructors.newenhancer = newenhancer

    local function setnewenhancer(format)

        local handler   = handlers[format]
        local enhancers = handler.enhancers

        if not enhancers then

            local actions  = allocate() -- no need to allocate thee
            local before   = allocate()
            local after    = allocate()
            local order    = allocate()
            local known    = { }
            local nofsteps = 0
            local patches  = { before = before, after = after }

            local trace   = false
            local report  = logs.reporter("fonts",format .. " enhancing")

            trackers.register(format .. ".loading", function(v) trace = v end)

            local function enhance(name,data,filename,raw)
                local enhancer = actions[name]
                if enhancer then
                    if trace then
                        report("apply enhancement %a to file %a",name,filename)
                        ioflush()
                    end
                    enhancer(data,filename,raw)
                else
                    -- no message as we can have private ones
                end
            end

            local function apply(data,filename,raw)
                local basename = file.basename(lower(filename))
                if trace then
                    report("%s enhancing file %a","start",filename)
                end
                ioflush() -- we want instant messages
                for e=1,nofsteps do
                    local enhancer = order[e]
                    local b = before[enhancer]
                    if b then
                        for pattern, action in next, b do
                            if find(basename,pattern) then
                                action(data,filename,raw)
                            end
                        end
                    end
                    enhance(enhancer,data,filename,raw) -- we have one installed: check extra features
                    local a = after[enhancer]
                    if a then
                        for pattern, action in next, a do
                            if find(basename,pattern) then
                                action(data,filename,raw)
                            end
                        end
                    end
                    ioflush() -- we want instant messages
                end
                if trace then
                    report("%s enhancing file %a","stop",filename)
                end
                ioflush() -- we want instant messages
            end

            local function register(what,action)
                if action then
                    if actions[what] then
                        -- overloading, e.g."check extra features"
                    else
                        nofsteps        = nofsteps + 1
                        order[nofsteps] = what
                        known[what]     = nofsteps
                    end
                    actions[what] = action
                else
                    report("bad enhancer %a",what)
                end
            end

            -- We used to have a lot of enhancers but no longer with the new font loader. The order of enhancers
            -- is the order of definition. The before/after patches are there for old times sake and happen
            -- before or after a (named) enhancer. An example of a set enhancer is "check extra features" so one
            -- one set patches before or after that is applied. Unknown enhancers are auto-registered. It's a bit
            -- messy but we keep it for compatibility reasons.
            --
            -- fonts.handlers.otf.enhancers.patches.register("before","some patches","somefont",function(data,filename)
            --     print("!!!!!!!") -- before | after
            -- end)
            --
            -- fonts.handlers.otf.enhancers.register("more patches",function(data,filename)
            --     print("???????") -- enhance
            -- end)

            local function patch(what,where,pattern,action)
                local pw = patches[what]
                if pw then
                    local ww = pw[where]
                    if ww then
                        ww[pattern] = action
                    else
                        pw[where] = { [pattern] = action }
                        if not known[where] then
                            nofsteps        = nofsteps + 1
                            order[nofsteps] = where
                            known[where]    = nofsteps
                        end
                    end
                end
            end

            enhancers = {
                register = register,
                apply    = apply,
                patch    = patch,
                report   = report,
                patches  = {
                    register = patch,
                    report   = report,
                }, -- for old times sake
            }

            handler.enhancers = enhancers
        end
        return enhancers
    end

    setmetatable(newenhancer, {
        __call  = function(t,k) local v = t[k] return v end,
        __index = function(t,k) local v = setnewenhancer(k) t[k] = v return v end,
    })

end

--[[ldx--
<p>We need to check for default features. For this we provide
a helper function.</p>
--ldx]]--

function constructors.checkedfeatures(what,features)
    local defaults = handlers[what].features.defaults
    if features and next(features) then
        features = fastcopy(features) -- can be inherited (mt) but then no loops possible
        for key, value in next, defaults do
            if features[key] == nil then
                features[key] = value
            end
        end
        return features
    else
        return fastcopy(defaults) -- we can change features in place
    end
end

-- before scaling

function constructors.initializefeatures(what,tfmdata,features,trace,report)
    if features and next(features) then
        local properties       = tfmdata.properties or { } -- brrr
        local whathandler      = handlers[what]
        local whatfeatures     = whathandler.features
        local whatmodechecker  = whatfeatures.modechecker
        -- properties.mode can be enforces (for instance in font-otd)
        local mode             = properties.mode or (whatmodechecker and whatmodechecker(tfmdata,features,features.mode)) or features.mode or "base"
        properties.mode        = mode -- also status
        features.mode          = mode -- both properties.mode or features.mode can be changed
        --
        local done             = { }
        while true do
            local redo = false
            local initializers = whatfeatures.initializers[mode]
            if initializers then
                for i=1,#initializers do
                    local step = initializers[i]
                    local feature = step.name
-- we could intercept mode here .. needs a rewrite of this whole loop then but it's cleaner that way
                    local value = features[feature]
                    if not value then
                        -- disabled
                    elseif done[feature] then
                        -- already done
                    else
                        local action = step.action
                        if trace then
                            report("initializing feature %a to %a for mode %a for font %a",feature,
                                value,mode,tfmdata.properties.fullname)
                        end
                        action(tfmdata,value,features) -- can set mode (e.g. goodies) so it can trigger a restart
                        if mode ~= properties.mode or mode ~= features.mode then
                            if whatmodechecker then
                                properties.mode = whatmodechecker(tfmdata,features,properties.mode) -- force checking
                                features.mode   = properties.mode
                            end
                            if mode ~= properties.mode then
                                mode = properties.mode
                                redo = true
                            end
                        end
                        done[feature] = true
                    end
                    if redo then
                        break
                    end
                end
                if not redo then
                    break
                end
            else
                break
            end
        end
        properties.mode = mode -- to be sure
        return true
    else
        return false
    end
end

-- while typesetting

function constructors.collectprocessors(what,tfmdata,features,trace,report)
    local processes    = { }
    local nofprocesses = 0
    if features and next(features) then
        local properties     = tfmdata.properties
        local whathandler    = handlers[what]
        local whatfeatures   = whathandler.features
        local whatprocessors = whatfeatures.processors
        local mode           = properties.mode
        local processors     = whatprocessors[mode]
        if processors then
            for i=1,#processors do
                local step = processors[i]
                local feature = step.name
                if features[feature] then
                    local action = step.action
                    if trace then
                        report("installing feature processor %a for mode %a for font %a",feature,mode,tfmdata.properties.fullname)
                    end
                    if action then
                        nofprocesses = nofprocesses + 1
                        processes[nofprocesses] = action
                    end
                end
            end
        elseif trace then
            report("no feature processors for mode %a for font %a",mode,properties.fullname)
        end
    end
    return processes
end

-- after scaling

function constructors.applymanipulators(what,tfmdata,features,trace,report)
    if features and next(features) then
        local properties       = tfmdata.properties
        local whathandler      = handlers[what]
        local whatfeatures     = whathandler.features
        local whatmanipulators = whatfeatures.manipulators
        local mode             = properties.mode
        local manipulators     = whatmanipulators[mode]
        if manipulators then
            for i=1,#manipulators do
                local step = manipulators[i]
                local feature = step.name
                local value = features[feature]
                if value then
                    local action = step.action
                    if trace then
                        report("applying feature manipulator %a for mode %a for font %a",feature,mode,properties.fullname)
                    end
                    if action then
                        action(tfmdata,feature,value)
                    end
                end
            end
        end
    end
end

function constructors.addcoreunicodes(unicodes) -- maybe make this a metatable if used at all
    if not unicodes then
        unicodes = { }
    end
    unicodes.space  = 0x0020
    unicodes.hyphen = 0x002D
    unicodes.zwj    = 0x200D
    unicodes.zwnj   = 0x200C
    return unicodes
end

-- -- keep for a while: old tounicode code
--
-- if changed then
--     -- basemode hack (we try to catch missing tounicodes, e.g. needed for ssty in math cambria)
--     local c = changed[unicode]
--     if c then
--      -- local ligatures = character.ligatures -- the original ligatures (as we cannot rely on remapping)
--         description = descriptions[c] or descriptions[unicode] or character
--         character = characters[c] or character
--         index = description.index or c
--         if tounicode then
--             touni = tounicode[index] -- nb: index!
--             if not touni then -- goodie
--                 local d = descriptions[unicode] or characters[unicode]
--                 local i = d.index or unicode
--                 touni = tounicode[i] -- nb: index!
--             end
--         end
--      -- if ligatures and not character.ligatures then
--      --     character.ligatures = ligatures -- the original targets (for now at least.. see libertine smallcaps)
--      -- end
--     else
--         description = descriptions[unicode] or character
--         index = description.index or unicode
--         if tounicode then
--             touni = tounicode[index] -- nb: index!
--         end
--     end
-- else
--     description = descriptions[unicode] or character
--     index = description.index or unicode
--     if tounicode then
--         touni = tounicode[index] -- nb: index!
--     end
-- end