stumbled across this thread looking for something else. it rises from the grave.
definitely NOT a rattan splitter. except possibly by necessity.
the OP's item is a thai pra or jungle knife. like many items, this is foremost a everyday tool carried into the jungle for slashing like a machete, or chopping vegetation, or general use. this particular one was used extensively over many years to clear encroaching vegetation in a thai villagers garden. i liberated it from him after he retired it. i'm assuming he uses power tools now
. sharp on the inside of the curve. also somewhat decorated blade. decorations look very much like the OP's blade except no brass slug. also a handy weapon if needed. mine is below. hardwood haft. edge faces down. probably comes from aranyik, have seen others almost exactly like it for sale from there. they call it something more specific than a pra, a generic term, i gather.
the mak is a bit different, tool and weapon, and rather odd and clumsy, they have a certain charm. mine, also below the pra, is set in a bamboo haft's root ball, which was grown curved back on itself. they were used in SE asia as pole arms by infantry and cavalry, as well as villager tools and self defence. i seem to recall getting this one on ebay...edge also faces down, and is well behind the haft line, making strikes a bit unusual.
both are just under 3 ft. pic of my wall next to my PC for scale.