if not modules then modules = { } end modules ['cldf-pos'] = {
    version   = 1.001,
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

-- https://cse512-19s.github.io/FP-Well-Rounded/

local tostring, load, type, tonumber  = tostring, load, type, tonumber
local lpegmatch = lpeg.match
local context = context

local setmetatableindex = table.setmetatableindex

local implement         = interfaces.implement

local fromposit         = posit.fromposit
local toposit           = posit.toposit
local posittonumber     = posit.tonumber

local values            = tokens.values
local boolean_code      = values.boolean

do

    local scanners          = tokens.scanners
    local scanfloat         = scanners.float
    local scaninteger       = scanners.integer
    local scancsname        = scanners.csname

    local codes             = tex.codes

    local global_code       = tex.flagcodes.global

    local savelua           = token.savelua
    ----- isdefined         = token.isdefined

    local newsparse         = sparse.new
    local setsparse         = sparse.set
    ----- wipesparse        = sparse.wipe
    local restoresparse     = sparse.restore

    local registerfunction  = context.functions.register

    implement {
        name      = "positunumdef",
        public    = true,
        untraced  = true,
        protected = true,
        actions   = function(what)
            local name    = scancsname(true)
            local code    = newsparse()
            local restore = registerfunction(function() restoresparse(code) end)
            implement {
                name      = name,
                public    = true,
                protected = true,
                usage     = "value",
                actions   = function(what)
                    local n = scaninteger()
                    if what == "value" then
                        local v = fromposit(code[n])
                     -- return float_code, v
                        context("%.99g",v)
                    else
                        local v = toposit(scanfloat())
                        if what and (tonumber(what) & global_code) then
                            setsparse(code,"global",n,v)
                        else
                            savelua(restore,true) -- only once
                            setsparse(code,n,v)
                        end
                    end
                end,
            }
            codes[name] = code
        end,
    }

end

do

    local p_number = lpeg.patterns.number
    local p = lpeg.Cs(
        lpeg.Cc("local new = new ; return ")
      * (
            lpeg.C(p_number) / function(s)
                 return "new(" .. s .. ")"
            end
            + lpeg.P(1)
        )^0
    )

    local t = setmetatableindex({ new = posit.new }, posit)

    local function calculate(s)
        local new = lpegmatch(p,s)
        new = load(new,nil,nil,t)
        if new then
            new = new()
            if new then
                return new
            end
        end
        return old
    end

    implement {
        name      = "positunum",
        public    = true,
        arguments = "string",
        actions   = function(s)
            local r = calculate(s)
            local t = type(r)
            if t == "boolean" then
                context(tostring(r))
            elseif t == "string" then
                context(r)
            else
                context("%N",posittonumber(r))
            end
        end
    }

    implement {
        name      = "ifpositunum",
        public    = true,
        usage     = "condition",
        arguments = "string",
        actions   = function(s)
            return boolean_code, calculate(s) and true or false
        end,
    }

end