--- this began long ago when a first test program for the Mandelbrot set went pear-shaped

 

local p={}



function chunk(text)

    local text=mw.ustring.gsub(text,"(%d%s*)E(%s*[%d%+%-])","%1 E %2") -- force space around E notation to avoid going nuts later

    local debuglog=""

    local chunks={type={}}

    local prowl=mw.ustring.gmatch(text,"(%S+)")

    local firstbit

    local num=1

    local op=2

    local var=3

    local warning=4

    local defs={num={"^([%d%.]*)(.*)$"},op={"^(E?)(.*)$","^([%(%)%*%+%-%?%%/!^]?)(.*)$"},var={"^(%a*)(.*)$"}}

    t=prowl()

    while t do

        local ot=t

        for i,j in pairs(defs) do

            for _,v in pairs(j) do

                firstbit,t=mw.ustring.match(t,v)

                debuglog=debuglog.."<"..tostring(firstbit)..","..tostring(t)..">"..tostring(i).."i"..tostring(j).."j"..tostring(t).."t"..tostring(v).."v"

                assert(t,debuglog) -- should always deliver a null string even if the target isn't there

                if firstbit ~= "" then

                    table.insert(chunks,firstbit)

                    table.insert(chunks.type,i)

                end

            end

        end

        if t==ot then

            firstbit,t=mw.ustring.match(t,"^(.)(.*)$")

            table.insert(chunks,'ignored:'..firstbit)

            table.insert(chunks.type,warning)

        end

        if t=="" then t=prowl() end -- if you run out of bits between spaces, pull a new interspace bit.

    end

    return chunks

end



function p.main(frame)

    local args=frame.args or {}

    local parent=frame.getParent(frame) or {}

    local pargs=parent.args or {}

    local expr=args.expr or pargs.expr or "" -- (Handle nothing in with nothing out?)

    local chunks=chunk(expr)

    return #chunks,"types"..table.concat(chunks.type,",").."values"..table.concat(chunks,",")

    -- check 1: getting the input sorted out into chunks

end



return p