% emulating Prolog in Oz

% rainy
declare Rainy Cold Snowy

fun {Rainy} choice seattle [] rochester end end
fun {Cold} rochester end

proc {Snowy X}
   {Rainy X}
   {Cold X}
end

{Browse {Search.base.all proc {$ C} {Rainy C} end}}

{Browse {Search.base.all Snowy}}

%family
declare
proc {Father X Y}
   choice X = bob Y = alice
   [] X=bob Y = peter
   end
end
proc {Mother X Y}
   choice X = carol Y = peter
   [] X = carol Y = alice
   end
end
proc {Sibling X Y}
   Z W in
   {Father Z X}
   {Mother W X}
   {Father Z Y}
   {Mother W Y}
   if X == Y then fail end
end

% calculate all
{Browse {Search.base.all proc {$ S} X Y in S=sib(X Y) {Sibling X Y} end}}

% append
declare Append
proc {Append Xs Ys Zs}
   choice Xs = nil Zs = Ys
   [] X Xr Zr in Xs=X|Xr Zs=X|Zr {Append Xr Ys Zr}
   end
end

% new search query
declare P
proc {P S} X Y in {Append X Y [1 2 3]} S=sol(X Y) end

% new search engine
declare E
E = {New Search.object script(P)}

% calculate and display one at a time
{Browse {E next($)}}

% calculate all
{Browse {Search.base.all
	 proc {$ S} X Y in
	    S=sol(X Y) {Append X Y [1 2 3]}
	 end}}