soulvialfarm

local function findItem(itemName)
    for i=1,16 do
        local itemDetail = turtle.getItemDetail(i);

        if itemDetail and itemDetail.name == itemName then
            return i;
        end
    end

    return -1;
end

local function digSand()
    local hasBlock, blockData = turtle.inspect();

    if hasBlock and blockData.name == "minecraft:sand" then
        turtle.dig();
    end
end

local function main()
    while true do
        digSand();
        local sandSlot = findItem("minecraft:sand");

        if sandSlot ~= -1 then
            turtle.select(sandSlot);
            turtle.dropUp();
        end

        local soulsandSlot = findItem("minecraft:soul_sand");

        if soulsandSlot ~= -1 and not turtle.detect() then
            turtle.select(soulsandSlot);
            turtle.place();
        end
    end
end

main();

-- DESIGN GOALS
-- 1. Place soul sand when in inventory.
-- 2. Mine sand if found in front of turtle.
-- 3. Drop sand upwards if found in inventory.