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

local trace_defining = false  trackers.register("math.defining", function(v) trace_defining = v end)
local report_math    = logs.reporter("mathematics","initializing")

local mathematics    = mathematics

local sequencers     = utilities.sequencers
local appendgroup    = sequencers.appendgroup
local appendaction   = sequencers.appendaction
local mathprocessor  = nil

local mathactions = sequencers.reset {
    arguments = "target,original",
}

function fonts.constructors.assignmathparameters(original,target)
    if mathactions.dirty then -- maybe use autocompile
        mathprocessor = sequencers.compile(mathactions)
    end
    mathprocessor(original,target)
end

appendgroup(mathactions,"before") -- user
appendgroup(mathactions,"system") -- private
appendgroup(mathactions,"after" ) -- user

function mathematics.initializeparameters(target,original)
    local mathparameters = original.mathparameters
    if mathparameters and next(mathparameters) then
        target.mathparameters = mathematics.dimensions(mathparameters)
    end
end

sequencers.appendaction(mathactions,"system","mathematics.initializeparameters")

local how = {
 -- RadicalKernBeforeDegree         = "horizontal",
 -- RadicalKernAfterDegree          = "horizontal",
    RadicalDegreeBottomRaisePercent = "unscaled"
}

function mathematics.scaleparameters(target,original)
    if not target.properties.math_is_scaled then
        local mathparameters = target.mathparameters
        if mathparameters and next(mathparameters) then
            local parameters = target.parameters
            local factor  = parameters.factor
            local hfactor = parameters.hfactor
            local vfactor = parameters.vfactor
            for name, value in next, mathparameters do
                local h = how[name]
                if h == "unscaled" then
                    mathparameters[name] = value
                elseif h == "horizontal" then
                    mathparameters[name] = value * hfactor
                elseif h == "vertical"then
                    mathparameters[name] = value * vfactor
                else
                    mathparameters[name] = value * factor
                end
            end
        end
        target.properties.math_is_scaled = true
    end
end

sequencers.appendaction(mathactions,"system","mathematics.scaleparameters")

function mathematics.checkaccentbaseheight(target,original)
    local mathparameters = target.mathparameters
    if mathparameters then
        mathparameters.AccentBaseHeight = nil -- safeguard
    end
end

sequencers.appendaction(mathactions,"system","mathematics.checkaccentbaseheight")

function mathematics.checkprivateparameters(target,original)
    local mathparameters = target.mathparameters
    if mathparameters then
        if not mathparameters.FractionDelimiterSize then
            mathparameters.FractionDelimiterSize = 0
        end
        if not mathparameters.FractionDelimiterDisplayStyleSize then
            mathparameters.FractionDelimiterDisplayStyleSize = 0
        end
    end
end

sequencers.appendaction(mathactions,"system","mathematics.checkprivateparameters")

function mathematics.overloadparameters(target,original)
    local mathparameters = target.mathparameters
    if mathparameters and next(mathparameters) then
        local goodies = target.goodies
        if goodies then
            for i=1,#goodies do
                local goodie = goodies[i]
                local mathematics = goodie.mathematics
                local parameters  = mathematics and mathematics.parameters
                if parameters then
                    if trace_defining then
                        report_math("overloading math parameters in '%s' @ %s",target.properties.fullname,target.parameters.size)
                    end
                    for name, value in next, parameters do
                        local tvalue = type(value)
                        if tvalue == "string" then
                            report_math("comment for math parameter '%s': %s",name,value)
                        else
                            local oldvalue = mathparameters[name]
                            local newvalue = oldvalue
                            if oldvalue then
                                if tvalue == "number" then
                                    newvalue = value
                                elseif tvalue == "function" then
                                    newvalue = value(oldvalue,target,original)
                                elseif not tvalue then
                                    newvalue = nil
                                end
                                if trace_defining and oldvalue ~= newvalue then
                                    report_math("overloading math parameter '%s': %s => %s",name,tostring(oldvalue),tostring(newvalue))
                                end
                            else
                                report_math("invalid math parameter '%s'",name)
                            end
                            mathparameters[name] = newvalue
                        end
                    end
                end
            end
        end
    end
end

sequencers.appendaction(mathactions,"system","mathematics.overloadparameters")