🚀 go-pugleaf

Instead of encoding the problem with a data-structure, one could encode it
with a program-structure. Functions become predicates:

properties(snow,white).
properties(snow,crystalline).
properties(snow,cold).

substances(white,snow).
substances(white,paper).
substances(white,salt).
substances(crystalline,snow).
substances(crystalline,salt).
substances(crystalline,diamond).
substances(cold,snow).
substances(cold,liquid_nitrogen).
substances(frozen,snow).
substances(frozen,ice_cream).

Adding that snow melts ar 32 degrees F:

:- assert(melting_point(snow,32_degrees_F)).

Asking the melting point of something white and frozen:

:- substances(white,S),substances(frozen,S),melting_point(S,MP).

yields S=snow, MP=32_degrees_F.

Thom Fruehwirth