is_functional(X) :-
    member(X, [scheme, racket, sml, haskell, scala, erlang, common_lisp,
           scala, mathematica, fsharp, mozart_oz, r, elisp]).

is_logical(X) :-
    member(X, [prolog, mini_karen, coq]).

is_oop(X) :-
    member(X, [ruby, python, scala, java, cplusplus, effiel]).

i_learned(X) :-
    member(X, [racket, sml, mathematica, fsharp, haskell, scala, common_lisp,
           mozart_oz, latex, chaos, fractal, complexity_system, analytics,
           sql, spark, hive, R, clojure, fsharp, android_programming, kotlin,
           algorithm, machine_learning, prolog, tableau, data_visualization,
           dvorak_layout, maltron_layout]).

i_like(X) :-
    member(X, [scheme,racket, sml, mathematica, haskell, fsharp, mozart_oz,
           chaos, fractal, prolog, algorithm, competitive_programming,
           complexity_system,cellular_automata, swimming, music, emacs,
           mini_karen, esperanto, japanese, sparsed_distributed_memory,
           tableau, data_visualization, maltron_layout]).

am_i_a_fan_of_declarative_programming :-
    is_functional(A), i_like(A), i_learned(A),
    is_logical(B), i_like(B), i_learned(B).
%% => true