-- Express configuration more sussunctly

local exp = {}
local types = {
	download = {},
	immediate = {},
	command = {},
}

for name, _ in pairs(types) do
	exp[name] = function(v)
		return {v, [types[name]] = true}
	end
	exp["is_" .. name] = function(tbl)
		return tbl[types[name]]
	end
end

-- Produce a string contains alfanum and underscore
exp.safe = function(s)
	return s:gsub("[^A-Za-z0-9]","-")
end

return exp