Initial source checkin

README.md

@@ -1,4 +1,74 @@
 prolog-examples
 ===============
 
-Some simple examples for new Prolog programmers
+Some simple examples for new Prolog programmers.
+Varying degrees of polish. Have fun.
+
+## finished examples
+
+###  detective problem
+
+These are two approaches to solving a detective's problem.
+She's interrogated three witnesses to a murder, all of whom are also suspects.
+The problem is to determine which of the suspect's testimony is
+inconsistent with the others.
+
+ * detectivepuzzle.pl
+ * adriandetective.pl
+
+### talespin2.pl
+
+Implementation of a classic story generator
+
+### tictactoe.pl
+
+Implementation of tic tac toe
+
+
+### birds.pl
+
+ The birds example from the 'expert systems in Prolog' tutorial
+ by Amzi (on the web)
+
+### cannibals2nocomments.pl
+
+ A well commented example of the cannibals/missionaries problem
+
+ This was used as an example for a talk whose notes are in may15version.txt
+
+### emoticons.pl 
+
+ A joke. I'm known for my happy array of 'smiley' emoticons. Sometimes others
+ have trouble understanding my smileys.  This program purports to help.
+
+### familytree.pl
+
+ The classic familytree example. This one has two separate families in it.
+ (left as exercise for the reader to find the two disconnected groups).
+
+### socketdemo.pl
+
+ Demonstration of reading from a socket
+
+## Constraint examples
+
+ Examples of CLPFD
+
+### addlists.pl
+
+ Constrains two lists to pairwise add to a third.
+
+### children.pl
+
+ A fully worked problem involving seating children in a classroom
+
+### constraintolist.pl
+
+ A fully worked problem, constraining a variable to be a member of a list.
+
+### sudoku.pl
+
+ Solves a Sudoku puzzle by CLPFD
+
+
+

addlists.pl

@@ -0,0 +1,9 @@
+:- use_module(library(clpfd)).
+
+addlists([], [], []).
+
+addlists([HA|TA],[HB|TB],[HC|TC]):-
+   HC #= HA+HB,
+   addlists(TA,TB,TC).
+
+

adriandetective.pl

@@ -0,0 +1,23 @@
+
+murderer(X) :- bagof(Y,contradictsPerson(X,Y),Ys), length(Ys,N), N > 1.
+
+contradictsPerson(A,B) :-
+claims(A,AClaims), claims(B,BClaims), contradictsClaims(AClaims,BClaims).
+
+contradictsClaims(Claims,[H|T]) :-
+contradictsClaims1(Claims,H); contradictsClaims(Claims,T).
+contradictsClaims1([H|T],C) :-
+contradictsClaim(H,C); contradictsClaims1(T,C).
+contradictsClaim([Claim1,Who],[Claim2,Who]) :-
+contradictory(Claim1,Claim2).
+
+claims(art,[[innocent,art],[knewVic,burt],[knewVic,carl]]).
+claims(burt,[[outOfTown,burt],[didNotKnowVic,burt]]).
+claims(carl,[[innocent,carl],[inTown,burt],[inTown,carl]]).
+
+contradictory(innocent,murderer).
+contradictory(murderer,innocent).
+contradictory(outOfTown,inTown).
+contradictory(inTown,outOfTown).
+contradictory(knewVic,didNotKnowVic).
+contradictory(didNotKnowVic,knewVic).

birds.pl

@@ -0,0 +1,156 @@
+:- module(birds, [solve/0]).
+
+:- dynamic
+	known/3,
+	voice/1,
+	season/1,
+	cheek/1,
+	head/1,
+	flight/1,
+	bill/1,
+	live/1,
+	nostrils/1.
+
+:- discontiguous bird/1, wings/1.
+:- set_prolog_flag(unknown, error).
+
+bird(laysan_albatross):-
+  family(albatross),
+  color(white).
+
+bird(black_footed_albatross):-
+  family(albatross),
+  color(dark).
+
+bird(whistling_swan) :-
+  family(swan),
+  voice(muffled_musical_whistle).
+
+bird(trumpeter_swan) :-
+  family(swan),
+  voice(loud_trumpeting).
+
+
+order(tubenose) :-
+nostrils(external_tubular),
+live(at_sea),
+bill(hooked).
+
+order(waterfowl) :-
+feet(webbed),
+bill(flat).
+
+family(albatross) :-
+order(tubenose),
+size(large),
+wings(long_narrow).
+
+family(swan) :-
+order(waterfowl),
+neck(long),
+color(white),
+flight(ponderous).
+
+bird(canada_goose):-
+family(goose),
+season(winter),
+country(united_states),
+head(black),
+cheek(white).
+
+bird(canada_goose):-
+family(goose),
+season(summer),
+country(canada),
+head(black),
+cheek(white).
+
+country(united_states):- region(mid_west).
+
+country(united_states):- region(south_west).
+
+country(united_states):- region(north_west).
+
+country(united_states):- region(mid_atlantic).
+
+country(canada):- province(ontario).
+
+country(canada):- province(quebec).
+
+region(new_england):-
+state(X),
+member(X, [massachusetts, vermont]).
+
+region(south_east):-
+state(X),
+member(X, [florida, mississippi]).
+
+state(X) :- member(X, [florida, mississippi, massachusetts, vermont]).
+
+province(X) :- member(X, [ontario, quebec]).
+
+ask(A, V):-
+  known(yes, A, V), % succeed if true
+  !. % stop looking
+
+ask(A, V):-
+  known(_, A, V), % fail if false
+  !, fail.
+
+% known is barfing
+ask(A, V):-
+  write(A:V), % ask user
+  write('? : '),
+  read(Y), % get the answer
+  asserta(known(Y, A, V)), % remember it
+  Y == yes. % succeed or fail
+ask(A, V):-
+	\+ multivalued(A),
+	known(yes, A, V2),
+	V \== V2,
+	!, fail.
+
+eats(X):- ask(eats, X).
+
+feet(X):- ask(feet, X).
+
+wings(X):- ask(wings, X).
+
+neck(X):- ask(neck, X).
+
+color(X):- ask(color, X).
+
+multivalued(voice).
+multivalued(feed).
+
+size(X):- menuask(size, X, [large, plump, medium, small]).
+
+flight(X):- menuask(flight, X, [ponderous, agile, flap_glide]).
+
+
+
+menuask(A, V, MenuList) :-
+write('What is the value for'), write(A), write('?'), nl,
+write(MenuList), nl,
+read(X),
+check_val(X, A, V, MenuList),
+asserta( known(yes, A, X) ),
+X == V.
+
+check_val(X, _A, _V, MenuList) :-
+member(X, MenuList), !.
+
+check_val(X, A, V, MenuList) :-
+write(X), write(' is not a legal value, try again.'), nl,
+menuask(A, V, MenuList).
+
+top_goal(X) :- bird(X).
+
+solve :-
+retractall(known/3),
+top_goal(X),
+write('The answer is '), write(X), nl.
+
+solve :-
+write('No answer found.'), nl.
+