convert index to custom subset

[fetsorn]

attempts to resolve #190

the bug was in on_metadata_inventory_take, it assumed that index parameter always matched default subset and fetched hardcoded costs for it.

instead, I find the proper index by searching for the given stack name in the names array.

[a-tour-ist]

I wounder whether it's worth keeping the cost_in_microblocks[custom_index] table.

Extracting the microblock type with a pattern and looking into a {type=cost} table might be more robust...

That would fix recycling custom_subset blocks too.

[fetsorn]

Extracting the microblock type with a pattern and looking into a {type=cost} table

How would you "extract type with a pattern"? I can do

circular_saw.blocks = {
	micro = { cost = 1, prefix = "micro", suffix = "" },
	micro_1 = { cost = 1, prefix = "micro", suffix = "_1" },

and then change ordered names to

circular_saw.names = {
    "micro_1",
    "panel_1",

and then figure out the type of the stack by matching it against all possible names. But I don't know if that would be more readable, and it'd still have the same efficiency as the current solution.

Do you think of something better?

[a-tour-ist]

How would you "extract type with a pattern"?

My idea was to do something like that:

function circular_saw:get_cost(inv, stackname)
	local input_stack = inv:get_stack("input",  1)
	local input_name = input_stack:get_name()
	local name_parts = circular_saw.known_nodes[input_name]
	local modname  = name_parts[1]
	local material = name_parts[2]
	local stackname = stack:get_name()
	stackname = minetest.registered_aliases[stackname] or stackname

	local pattern = "^" .. modname .. ":(.*)_" .. material .. "(.*)$"
	local prefix, suffix = string.match(stackname, pattern)

	-- TODO: populate this table somewhere and give it a better name
	return costs[prefix..suffix]
end

[fetsorn]

I see what you mean about the pattern now! Updated the PR.

[SmallJoker]

Wouldn't it be more straight-forward to have the cost included As a Node Definition field, such as _circular_saw_cost = n? That would avoid possibly error-prone pattern matching (e.g. where the material might contain _).

[fetsorn]

cost is now in the microblock node definition. I changed the slab data structure in defs.lua a bit to make it more like the rest of the definition tables.

stair_right_half is the only def without a cost and not mentioned in circular saw. Is that a bug or on purpose?

[SmallJoker]

stair_right_half is the only def without a cost and not mentioned in circular saw. Is that a bug or on purpose?

For the scope of this PR I would suggest to add a TODO FIXME-alike comment in the code to highlight this inconsistency.

[SmallJoker]

Looks good. Thank you. Will merge in a few days unless there are objections.