🚀 go-pugleaf

Karen's program fails when it gets to the write/1 predicate.  In Arity/Prolog
we have visible declarations, which are a way to tell the interpreter which
predicates are to be visible at run-time.  Having all the builtins visible
for every standalone application would force them all to be linked in to
every standalone application, making them bigger than they would otherwise
have to be.  Therefore, we let the programmer either decide that 

(i) all builtins should be visible,  or
(ii) only selected ones (which is the default)

In the case in question, the insertion of the line:

:- visible write/1.

in the first file would cause the program to work correctly.