getFuelValue.lua

---- finds out which item it is and what fuel
function getFuelFromTable(tab,value)
    for i,v in pairs(tab) do
        local a = v[1]  -- name of item
        local b = v[2]  -- heating value

        local valueClipped = ""

        local char1 = string.sub(a,1,1)
        if char1 == "*" then
                a = string.sub(a,2,-1)
                --crazy work around that allows wildcard-like functionality
                --> if the last characters of 'a' are the same as the last characters of 'value' then true
                local aLen = string.len(a)
                valueClipped = string.sub(value,-aLen,-1)
                --print(a)
        else
                valueClipped = value
        end


        if a == valueClipped then
            return b
        end
    end

    --not found
    return false

end



function getFuelValue(fuelSlot)
            local stdFuelValues = {
                    {"minecraft:charcoal",80},
                    {"minecraft:coal",80},
                    {"minecraft:stick",5},
                    {"minecraft:lava_bucket",1000},
                    {"*_log",15},
                    {"*_planks",15},
                    {"*_plank",15},
                    {"*_planks_slab",15},
                    {"*_chest",15},
                    {"*_wool",5}

            }

            local prevSlot = turtle.getSelectedSlot()

            --change slots, if neccesary
            if prevSlot ~= fuelSlot then
                    turtle.select(fuelSlot)
            end

            --get the name of the item in fuel slot
            local a,b = turtle.getItemDetail()
            if a ~= nil then
                local name = a.name
                a=nil; b=nil

                local fuelValue = getFuelFromTable(stdFuelValues,name)
                return fuelValue
            else

            end

            --change slots back, if neccesary
            if fuelSlot ~= prevSlot then
                    turtle.select(prevSlot)
            end

            return nil



end

--local fslot = 1
--getFuelValue(fslot)

return getFuelValue