CREATE OR REPLACE FUNCTION field(value TEXT, VARIADIC arr TEXT[])
RETURNS INT AS $$
DECLARE
    i INT;
BEGIN
    FOR i IN 1 .. array_length(arr, 1) LOOP
        IF arr[i] = value THEN
            RETURN i;
        END IF;
    END LOOP;
    RETURN 0;
END;
$$ LANGUAGE plpgsql IMMUTABLE;