swaa

local swaa = {
    case = function(sw,case,func)
        sw.cases[case] = func; return sw
    end,
    case_list = function(sw,func,...)
        for _,v in next,{...} do sw:case(v,func) end
        return sw
    end,
    case_range = function(sw,caseA,caseB,func)
        sw.range_cases[#sw.range_cases+1] = { caseA,caseB,func }
        return sw
    end,
    close = function(sw)
        if tonumber(sw.v) then
            for _,v in next,sw.range_cases do
                if sw.v>=v[1] and sw.v<=v[2] then return v[3](sw.v) end
            end
        end
        return (sw.cases[sw.v or "default"] or sw.cases["default"])(sw.v)
    end
}
swaa.__index = swaa

local function swaa_new(v)
    local cases = { default = function(v) end }
    local range_cases = {}
    return setmetatable({v=v,cases=cases,range_cases=range_cases,close=nil},swaa)
end

local switch = swaa_new

print(
    switch(0)
        :case_range(0,7,function(v) print("between 0-7") return -1 end)
        :case_list(function(v) print("between 11-12") return v-8 end,11,12)
        :case(8,function(v) return 0 end)
        :case(9,function(v) return 1 end)
        :case(10,function(v) return 2 end)
        :close()
)