blockgame/mods/bg_stoneworking/recipe.lua

local modname = minetest.get_current_modname()

local function is_stoney_below (pos)
	local below_node = minetest.get_node(pos + blockgame.vector.dirs.down)
	return blockgame.item_matches(below_node.name, {"group:stoney"})
end

blockgame.crafting.register_pummel_recipe({
	name = modname .. ":craft_tile",
	label = "pummel stone into tile",
	used = {"group:stoney"},
	target = {"bg_terrain:cobblestone"},
	check = function (pos, used_node, target_node)
		return is_stoney_below(pos)
	end,
	on_success = function (pos, used_node, target_node)
		minetest.set_node(pos, {name = modname .. ":tile"})
	end,
})

blockgame.crafting.register_pummel_recipe({
	name = modname .. ":craft_bricks",
	label = "pummel tile into bricks",
	used = {"group:stoney"},
	target = {modname .. ":tile"},
	check = function (pos, used_node, target_node)
		return is_stoney_below(pos)
	end,
	on_success = function (pos, used_node, target_node)
		minetest.set_node(pos, {name = modname .. ":bricks"})
	end,
})