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-- Programmed by Jedidiah Barber
-- Licensed under the Sunset License v1.0
-- See license.txt for further details
-- 1. There are five houses in a row, each of a different color
-- and inhabited by men of different nationalities,
-- with different pets, drinks, and cigarettes.
-- 2. The Englishman lives in the red house.
-- 3. The Spaniard owns a dog.
-- 4. Coffee is drunk in the green house.
-- 5. The Ukrainian drinks tea.
-- 6. The green house is directly to the right of the ivory house.
-- 7. The Old Gold smoker owns snails.
-- 8. Kools are being smoked in the yellow house.
-- 9. Milk is drunk in the middle house.
-- 10. The Norwegian lives in the first house on the left.
-- 11. The Chesterfield smoker lives next to the fox owner.
-- 12. Kools are smoked in the house next to the house where the horse is kept.
-- 13. The Lucky Strike smoker drinks orange juice.
-- 14. The Japanese smokes Parliaments.
-- 15. The Norwegian lives next to the blue house.
with
Ada.Strings.Unbounded,
Ada.Text_IO,
Kompsos.Pretty_Print;
procedure Zebra is
package SU renames Ada.Strings.Unbounded;
package TIO renames Ada.Text_IO;
function "+"
(Item : in String)
return SU.Unbounded_String
renames SU.To_Unbounded_String;
package SKomp is new Kompsos (SU.Unbounded_String);
use SKomp;
package Printer is new SKomp.Pretty_Print (SU.To_String);
function On_Right
(This : in World;
Inputs : in Term_Array)
return World;
function On_Right
(This : in World;
Inputs : in Term_Array)
return World
is
Left_Term : Term renames Inputs (1);
Right_Term : Term renames Inputs (2);
List_Term : Term renames Inputs (3);
One, Two : World := This;
One_Ref : constant Term := One.Fresh;
Two_Ref : constant Term := Two.Fresh;
begin
One.Head (List_Term & Left_Term);
One.Tail (List_Term & One_Ref);
One.Head (One_Ref & Right_Term);
Two.Tail (List_Term & Two_Ref);
Two.Conjunct (On_Right'Access, Left_Term & Right_Term & Two_Ref);
return Disjunct (One, Two);
end On_Right;
function Next_To
(This : in World;
Inputs : in Term_Array)
return World
is
Left_Term : Term renames Inputs (1);
Right_Term : Term renames Inputs (2);
List_Term : Term renames Inputs (3);
begin
return Disjunct
(On_Right (This, Left_Term & Right_Term & List_Term),
On_Right (This, Right_Term & Left_Term & List_Term));
end Next_To;
Verse : World := Empty_World;
function N is new Make_Fresh (Verse);
Houses : constant Term_Array := N & N & N & N & N;
Houses_Term : constant Term := T (Houses);
Result : State;
begin
Verse.Unify (Houses (1), T (T (+"norwegian") & N & N & N & N));
Verse.Unify (Houses (3), T (N & N & T (+"milk") & N & N));
Verse.Member (T (T (+"englishman") & N & N & N & T (+"red")) & Houses_Term);
Verse.Member (T (N & T (+"kools") & N & N & T (+"yellow")) & Houses_Term);
Verse.Member (T (T (+"spaniard") & N & N & T (+"dog") & N) & Houses_Term);
Verse.Member (T (N & N & T (+"coffee") & N & T (+"green")) & Houses_Term);
Verse.Member (T (T (+"ukrainian") & N & T (+"tea") & N & N) & Houses_Term);
Verse.Member (T (N & T (+"luckystrikes") & T (+"oj") & N & N) & Houses_Term);
Verse.Member (T (T (+"japanese") & T (+"parliaments") & N & N & N) & Houses_Term);
Verse.Member (T (N & T (+"oldgolds") & N & T (+"snails") & N) & Houses_Term);
Verse := On_Right (Verse,
T (N & N & N & N & T (+"ivory")) &
T (N & N & N & N & T (+"green")) & Houses_Term);
Verse := Next_To (Verse,
T (T (+"norwegian") & N & N & N & N) &
T (N & N & N & N & T (+"blue")) & Houses_Term);
Verse := Next_To (Verse,
T (N & N & N & T (+"horse") & N) &
T (N & T (+"kools") & N & N & N) & Houses_Term);
Verse := Next_To (Verse,
T (N & N & N & T (+"fox") & N) &
T (N & T (+"chesterfields") & N & N & N) & Houses_Term);
Verse.Force (1);
Verse.Member (T (N & N & T (+"water") & N & N) & Houses_Term);
Verse.Member (T (N & N & N & T (+"zebra") & N) & Houses_Term);
Result := Verse.Take_First;
for House of Houses loop
TIO.Put_Line (Printer.Image (House.Resolve (Result)));
end loop;
end Zebra;
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