Welcome to SWI-Prolog (threaded, 64 bits, version 8.0.3)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.
For online help and background, visit http://www.swi-prolog.org
For built-in help, use ?- help(Topic). or ?- apropos(Word).
?- consult('gv.pl').
true.
?- declare(x, 1).
true.
?- declare(y, 5).
true.
?- value_of(x, Value).
Value = 1.
?- bind(x, 3).
true.
?- display_bindings.
y -> 5
x -> 3
true.
?- inc(x).
true.
?- dec(y).
true.
?- display_bindings.
x -> 4
y -> 4
true.
?- add(x, Y), value_of(y, Y).
ERROR: Arguments are not sufficiently instantiated
ERROR: In:
ERROR: [10] _8340 is 4+_8348
ERROR: [9] add(x,_8374) at /home/zeno/Documents/Oswego/2019_Fall/csc366/csc366/hw3/gv.pl:36
ERROR: [8] '