On Monday, June 11, 2012 5:31:41 PM UTC+2, Jim foo.bar wrote: > > Thanks a million mnicky!!! > A simple explanation like yours is just what I needed...I think i get > the rationale... >
You are welcome :) > however, how would I know which of the 8 functions to call when the time > comes to consume it? I can see 8 move predicates with identical > signatures...how would i call them and how would the system know which one > to fire? > That's just an implementation detail, but basically we could say that Prolog tries all of them and uses only those with all body conditions satisfied (when the variables are substituted with values provided in the arguments). But this shouldn't pose any problem to you. As I said, I really don't know core.logic well, but AFAIK you just should put all the 8 sets of the conditions to the "conde" macro, each one as a separate statement, or sth like that... Looking at the core.logic intro by Stuart Sierra [1], it could be sth like this (but this probably isn't even correct): (let [xmax 8, ymax 8] (run 1 [a b] (conde [(< (+ x 1) xmax) (< (+ y 2) ymax) (== a (+ x 1)) (== b (+ y 2))] ;1st [(< (+ x 2) xmax) (< (+ y 1) ymax) (== a (+ x 2)) (== b (+ y 1))] ;2nd ... ))) > I may disturb you again in the near future perhaps once I dive deeper into > logic...I also need to learn how to translate prolog syntax to > core.logic.... > You can probably substitute the "is" operator of Prolog with the "==" operator of core.logic, but very likely you will have to define your own "greather than" and "lower than" operators... Marek. [1] http://clojure.com/blog/2011/12/08/lojic-part-two.html > > Jim > > > On 11/06/12 13:00, mnicky wrote: > > Although I am familiar with Prolog, I'm not very familiar with core.logic > yet :-( > But maybe I can provide you an explanation of that Prolog code and you can > derive the core.logic implementation by yourself... > > All clauses you provided define one predicate, move(), which has two > arguments and both of them are lists of four variables (e.g. [A,B,C,D] is > also a list of four variables). > > This predicate defines a relationship between those two lists. > Given the first list with provided concrete values, the predicate will > assign all possible values to the elements of the second list. > > These values must fulfill the contract, defined by the body of the > predicate... > > E.g. let's take this one: > > --------------- > move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- > X + 1 < Xmax, > Y + 2 < Ymax, > A is X + 1, > B is Y + 2. > --------------- > > This basically means, that if you call: "move([1, 2, 5, 6], [A, B, Xmax, > Ymax])." > you will be given all the possible values of A, B, Xmax and Ymax such that > this will hold true: > X + 1 < Xmax && Y + 2 < Ymax && A = X + 1 && B = Y + 2 > > concretely, you will receive the values: > A = 2, > B = 4, > Xmax = 5, > Ymax = 6. > > (The last two are the same that were provided when calling the > predicate.) > > The last information is, that there is a "logical OR" between all the 8 > provided "move()" expressions, so that whichever of them can found at least > one valid solution, it will be used. It's like as if they were the lines of > a "conde" in core.logic. > > > I hope that this can help you at least a little. > If you have any questions, just ask ;-) > > Marek. > > P.S. My apologize to all the Prolog programmers here for simplified (and > not always correct) Prolog terminology... > > > On Monday, June 11, 2012 12:25:49 PM UTC+2, Jim foo.bar wrote: >> >> I managed to find this piece of prolog code in >> http://bkraabel.free.fr/pages/kmoves_pl.html#top >> of page <http://bkraabel.free.fr/pages/kmoves_pl.html#top%20of%20page>but I >> don't know how to read it! Can anyone help me translate that to >> core.logic so i have a starting point? checkers also move similarly to >> knights (but just one position at a time)... >> >> % The following 8 moves define all the possible moves a knight >> % may make on a chess board, without leaving the chess board. The >> % size of the chess board is given by (Xmax, Ymax). >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 1 < Xmax, >> Y + 2 < Ymax, >> A is X + 1, >> B is Y + 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 2 < Xmax, >> Y + 1 < Ymax, >> A is X + 2, >> B is Y + 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 2 < Xmax, >> Y - 1 >= 0, >> A is X + 2, >> B is Y - 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 1 < Xmax, >> Y - 2 >= 0, >> A is X + 1, >> B is Y - 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 1 >= 0, >> Y - 2 >= 0, >> A is X - 1, >> B is Y - 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 2 >= 0, >> Y - 1 >= 0, >> A is X - 2, >> B is Y - 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 2 >= 0, >> Y + 1 < Ymax, >> A is X - 2, >> B is Y + 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 1 >= 0, >> Y + 2 < Ymax, >> A is X - 1, >> B is Y + 2. >> >> >> Jim >> >> On 11/06/12 01:09, Jim - FooBar(); wrote: >> >> Hello everyone, >> >> I'm trying to decide if its worth writing the rules of chess/checkers >> using core.logic or go down the conventional road but unfortunately I'm >> inexperienced as far as core.logic goes. I mean I've played around for a >> bit but nothing serious. >> >> What I want is NOT AI or anything like that...all I want is to encode the >> rules of the game somehow so i can then pass a board and a piece to some >> function that will be able to find all available moves that don't violate >> the rules of the game - no picking the best move or anything like >> that...just finding the legal moves efficiently...does this sound >> reasonable? I'm surprised there are so little on-line resources on the >> matter! >> >> if someone can explain the advantages and the disadvantages of of doing >> so that would be fanatstic...Even better if someone can point me in the >> right direction (some similar project perhaps). I really have no idea how >> to start and its one of the few times g8ggle doesn't seem to help... >> >> thanks in advance... >> >> >> Jim >> >> >> -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > > > On Monday, June 11, 2012 5:31:41 PM UTC+2, Jim foo.bar wrote: > > Thanks a million mnicky!!! > A simple explanation like yours is just what I needed...I think i get the > rationale... > > however, how would I know which of the 8 functions to call when the time > comes to consume it? I can see 8 move predicates with identical > signatures...how would i call them and how would the system know which one > to fire? > > I may disturb you again in the near future perhaps once I dive deeper into > logic...I also need to learn how to translate prolog syntax to > core.logic.... > > Jim > > > On 11/06/12 13:00, mnicky wrote: > > Although I am familiar with Prolog, I'm not very familiar with core.logic > yet :-( > But maybe I can provide you an explanation of that Prolog code and you can > derive the core.logic implementation by yourself... > > All clauses you provided define one predicate, move(), which has two > arguments and both of them are lists of four variables (e.g. [A,B,C,D] is > also a list of four variables). > > This predicate defines a relationship between those two lists. > Given the first list with provided concrete values, the predicate will > assign all possible values to the elements of the second list. > > These values must fulfill the contract, defined by the body of the > predicate... > > E.g. let's take this one: > > --------------- > move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- > X + 1 < Xmax, > Y + 2 < Ymax, > A is X + 1, > B is Y + 2. > --------------- > > This basically means, that if you call: "move([1, 2, 5, 6], [A, B, Xmax, > Ymax])." > you will be given all the possible values of A, B, Xmax and Ymax such that > this will hold true: > X + 1 < Xmax && Y + 2 < Ymax && A = X + 1 && B = Y + 2 > > concretely, you will receive the values: > A = 2, > B = 4, > Xmax = 5, > Ymax = 6. > > (The last two are the same that were provided when calling the > predicate.) > > The last information is, that there is a "logical OR" between all the 8 > provided "move()" expressions, so that whichever of them can found at least > one valid solution, it will be used. It's like as if they were the lines of > a "conde" in core.logic. > > > I hope that this can help you at least a little. > If you have any questions, just ask ;-) > > Marek. > > P.S. My apologize to all the Prolog programmers here for simplified (and > not always correct) Prolog terminology... > > > On Monday, June 11, 2012 12:25:49 PM UTC+2, Jim foo.bar wrote: >> >> I managed to find this piece of prolog code in >> http://bkraabel.free.fr/pages/kmoves_pl.html#top >> of page <http://bkraabel.free.fr/pages/kmoves_pl.html#top%20of%20page>but I >> don't know how to read it! Can anyone help me translate that to >> core.logic so i have a starting point? checkers also move similarly to >> knights (but just one position at a time)... >> >> % The following 8 moves define all the possible moves a knight >> % may make on a chess board, without leaving the chess board. The >> % size of the chess board is given by (Xmax, Ymax). >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 1 < Xmax, >> Y + 2 < Ymax, >> A is X + 1, >> B is Y + 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 2 < Xmax, >> Y + 1 < Ymax, >> A is X + 2, >> B is Y + 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 2 < Xmax, >> Y - 1 >= 0, >> A is X + 2, >> B is Y - 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 1 < Xmax, >> Y - 2 >= 0, >> A is X + 1, >> B is Y - 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 1 >= 0, >> Y - 2 >= 0, >> A is X - 1, >> B is Y - 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 2 >= 0, >> Y - 1 >= 0, >> A is X - 2, >> B is Y - 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 2 >= 0, >> Y + 1 < Ymax, >> A is X - 2, >> B is Y + 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 1 >= 0, >> Y + 2 < Ymax, >> A is X - 1, >> B is Y + 2. >> >> >> Jim >> >> On 11/06/12 01:09, Jim - FooBar(); wrote: >> >> Hello everyone, >> >> I'm trying to decide if its worth writing the rules of chess/checkers >> using core.logic or go down the conventional road but unfortunately I'm >> inexperienced as far as core.logic goes. I mean I've played around for a >> bit but nothing serious. >> >> What I want is NOT AI or anything like that...all I want is to encode the >> rules of the game somehow so i can then pass a board and a piece to some >> function that will be able to find all available moves that don't violate >> the rules of the game - no picking the best move or anything like >> that...just finding the legal moves efficiently...does this sound >> reasonable? I'm surprised there are so little on-line resources on the >> matter! >> >> if someone can explain the advantages and the disadvantages of of doing >> so that would be fanatstic...Even better if someone can point me in the >> right direction (some similar project perhaps). I really have no idea how >> to start and its one of the few times g8ggle doesn't seem to help... >> >> thanks in advance... >> >> >> Jim >> >> >> -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > > > On Monday, June 11, 2012 5:31:41 PM UTC+2, Jim foo.bar wrote: > > Thanks a million mnicky!!! > A simple explanation like yours is just what I needed...I think i get the > rationale... > > however, how would I know which of the 8 functions to call when the time > comes to consume it? I can see 8 move predicates with identical > signatures...how would i call them and how would the system know which one > to fire? > > I may disturb you again in the near future perhaps once I dive deeper into > logic...I also need to learn how to translate prolog syntax to > core.logic.... > > Jim > > > On 11/06/12 13:00, mnicky wrote: > > Although I am familiar with Prolog, I'm not very familiar with core.logic > yet :-( > But maybe I can provide you an explanation of that Prolog code and you can > derive the core.logic implementation by yourself... > > All clauses you provided define one predicate, move(), which has two > arguments and both of them are lists of four variables (e.g. [A,B,C,D] is > also a list of four variables). > > This predicate defines a relationship between those two lists. > Given the first list with provided concrete values, the predicate will > assign all possible values to the elements of the second list. > > These values must fulfill the contract, defined by the body of the > predicate... > > E.g. let's take this one: > > --------------- > move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- > X + 1 < Xmax, > Y + 2 < Ymax, > A is X + 1, > B is Y + 2. > --------------- > > This basically means, that if you call: "move([1, 2, 5, 6], [A, B, Xmax, > Ymax])." > you will be given all the possible values of A, B, Xmax and Ymax such that > this will hold true: > X + 1 < Xmax && Y + 2 < Ymax && A = X + 1 && B = Y + 2 > > concretely, you will receive the values: > A = 2, > B = 4, > Xmax = 5, > Ymax = 6. > > (The last two are the same that were provided when calling the > predicate.) > > The last information is, that there is a "logical OR" between all the 8 > provided "move()" expressions, so that whichever of them can found at least > one valid solution, it will be used. It's like as if they were the lines of > a "conde" in core.logic. > > > I hope that this can help you at least a little. > If you have any questions, just ask ;-) > > Marek. > > P.S. My apologize to all the Prolog programmers here for simplified (and > not always correct) Prolog terminology... > > > On Monday, June 11, 2012 12:25:49 PM UTC+2, Jim foo.bar wrote: >> >> I managed to find this piece of prolog code in >> http://bkraabel.free.fr/pages/kmoves_pl.html#top >> of page <http://bkraabel.free.fr/pages/kmoves_pl.html#top%20of%20page>but I >> don't know how to read it! Can anyone help me translate that to >> core.logic so i have a starting point? checkers also move similarly to >> knights (but just one position at a time)... >> >> % The following 8 moves define all the possible moves a knight >> % may make on a chess board, without leaving the chess board. The >> % size of the chess board is given by (Xmax, Ymax). >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 1 < Xmax, >> Y + 2 < Ymax, >> A is X + 1, >> B is Y + 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 2 < Xmax, >> Y + 1 < Ymax, >> A is X + 2, >> B is Y + 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 2 < Xmax, >> Y - 1 >= 0, >> A is X + 2, >> B is Y - 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X + 1 < Xmax, >> Y - 2 >= 0, >> A is X + 1, >> B is Y - 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 1 >= 0, >> Y - 2 >= 0, >> A is X - 1, >> B is Y - 2. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 2 >= 0, >> Y - 1 >= 0, >> A is X - 2, >> B is Y - 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 2 >= 0, >> Y + 1 < Ymax, >> A is X - 2, >> B is Y + 1. >> >> move([X, Y, Xmax, Ymax], [A, B, Xmax, Ymax]) :- >> X - 1 >= 0, >> Y + 2 < Ymax, >> A is X - 1, >> B is Y + 2. >> >> >> Jim >> >> On 11/06/12 01:09, Jim - FooBar(); wrote: >> >> Hello everyone, >> >> I'm trying to decide if its worth writing the rules of chess/checkers >> using core.logic or go down the conventional road but unfortunately I'm >> inexperienced as far as core.logic goes. I mean I've played around for a >> bit but nothing serious. >> >> What I want is NOT AI or anything like that...all I want is to encode the >> rules of the game somehow so i can then pass a board and a piece to some >> function that will be able to find all available moves that don't violate >> the rules of the game - no picking the best move or anything like >> that...just finding the legal moves efficiently...does this sound >> reasonable? I'm surprised there are so little on-line resources on the >> matter! >> >> if someone can explain the advantages and the disadvantages of of doing >> so that would be fanatstic...Even better if someone can point me in the >> right direction (some similar project perhaps). I really have no idea how >> to start and its one of the few times g8ggle doesn't seem to help... >> >> thanks in advance... >> >> >> Jim >> >> >> -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
