% compile this program using "gplc hworld.pl --no-top-level"
%

put_codes( [C|[]] ) :- put_code( C ).
put_codes( [C|Cs] ) :- put_code( C ),
                       put_codes( Cs ).

main :- append( "Hello, ", "world!\n", Str ),
        put_codes( Str ).

:- initialization( main ).


%%%%%%%%%%
% Question: what happens if you define the main predicate "backwards"?
% For example:
%
%    main :- put_codes( Str ),
%            append( "Hello, ", "world!\n", Str ).
%
% Why does this happen?
%%%%%%%%%%