BlockType constants?

[Nixtren]

Hi,

Suppose the following function:

function OnPlayerPlacingBlock(Player, BlockX, BlockY, BlockZ, BlockType, BlockMeta)

Is there any way to do something like this?

if BlockType == BLOCKTYPE_CHEST then
    -- Do something
end

It's because I don't like the ideia of determining the BlockType by experimental ways, are there any constants like these? I couldn't find any.