function randprob_from(l)
	--the function expects an
	--array of tables like these:
	--{p=0.5,v='item name'}

	--a "p" value between 0 and 1
	--and a "v" value.

	--"p" is propability of the
	--"v" value being returned

	local lim=1
	local value=rnd()
	for pos in all(l) do
		highlimit=lim
		lim-=pos.p
		lowlimit=lim
		if value<highlimit
		and value>=lowlimit then
			return pos.v
		end
	end
end