metafilter

type FilterFunction func(
	parameter string,
	value_to_match interface{},
) (bool, error)

type FilterFunctions map[string]FilterFunction

type FilterItem struct {
	// if [function result]+[NotFunc] == true.
	// if Add == true, then value which is chacked by this filter item,
	// considered to be added to result,
	// else, if Add == false, - item should be removed from result
	Add bool

	// apply boolean not to function result
	NotFunc bool

	// name of function, which FilterList have to use
	Func string

	// some functioning data, to be passed to function
	FuncParam string
}

type Filters []*FilterItem