  Fuzzy logic programming is a growing declarative paradigm aiming to integrate
fuzzy logic into logic programming. One of the most difficult tasks when
specifying a fuzzy logic program is determining the right weights for each
rule, as well as the most appropriate fuzzy connectives and operators. In this
paper, we introduce a symbolic extension of fuzzy logic programs in which some
of these parameters can be left unknown, so that the user can easily see the
impact of their possible values. Furthermore, given a number of test cases, the
most appropriate values for these parameters can be automatically computed.
