Added the sudoku example

examples/father.py

@@ -21,7 +21,6 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-from __future__ import print_function
 from pyswip import *
 
 

examples/register_foreign_simple.py

@@ -23,7 +23,6 @@
 
 # Demonstrates registering a Python function as a Prolog predicate through SWI-Prolog's FFI.
 
-from __future__ import print_function
 from pyswip.prolog import Prolog
 from pyswip.easy import registerForeign
 

examples/sudoku/sudoku.py

@@ -21,9 +21,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-from __future__ import print_function
 from pyswip.prolog import Prolog
-from pyswip.easy import *
 
 
 _ = 0
@@ -61,7 +59,7 @@ def pretty_print(table):
 
 
 def solve(problem):
-    prolog.consult("sudoku.pl")
+    prolog.consult("sudoku.pl", relative_to=__file__)
     p = str(problem).replace("0", "_")
     result = list(prolog.query("L=%s,sudoku(L)" % p, maxresult=1))
     if result:

examples/sudoku/sudoku_daily.py

@@ -25,14 +25,11 @@
 # Sudoku auto-solver. Get today's sudoku at http://www.sudoku.org.uk/daily.asp
 # and solve it
 
-from __future__ import print_function
-from pyswip.prolog import Prolog
-from pyswip.easy import *
-
 from html.parser import HTMLParser
-
 import urllib.request as urllib_request
 
+from pyswip.prolog import Prolog
+
 
 class DailySudokuPuzzle(HTMLParser):
     def __init__(self):
@@ -75,7 +72,7 @@ def get_daily_sudoku(url):
 
 
 def solve(problem):
-    prolog.consult("sudoku.pl")
+    prolog.consult("sudoku.pl", relative_to=__file__)
     p = str(problem).replace("0", "_")
     result = list(prolog.query("Puzzle=%s,sudoku(Puzzle)" % p, maxresult=1))
     if result:
@@ -94,7 +91,7 @@ def solve(problem):
     print("-- PUZZLE --")
     pretty_print(puzzle)
     print()
-    print(" -- SOLUTION --")
+    print("-- SOLUTION --")
     solution = solve(puzzle)
     if solution:
         pretty_print(solution)

src/pyswip/examples/sudoku.pl

@@ -0,0 +1,26 @@
+
+% Prolog Sudoku Solver (C) 2007 Markus Triska ([email protected])
+% Public domain code.
+
+:- use_module(library(bounds)).
+
+% Pss is a list of lists representing the game board.
+
+sudoku(Pss) :-
+    flatten(Pss, Ps),
+    Ps in 1..9,
+    maplist(all_different, Pss),
+    Pss = [R1,R2,R3,R4,R5,R6,R7,R8,R9],
+    columns(R1, R2, R3, R4, R5, R6, R7, R8, R9),
+    blocks(R1, R2, R3), blocks(R4, R5, R6), blocks(R7, R8, R9),
+    label(Ps).
+
+columns([], [], [], [], [], [], [], [], []).
+columns([A|As],[B|Bs],[C|Cs],[D|Ds],[E|Es],[F|Fs],[G|Gs],[H|Hs],[I|Is]) :-
+    all_different([A,B,C,D,E,F,G,H,I]),
+    columns(As, Bs, Cs, Ds, Es, Fs, Gs, Hs, Is).
+
+blocks([], [], []).
+blocks([X1,X2,X3|R1], [X4,X5,X6|R2], [X7,X8,X9|R3]) :-
+    all_different([X1,X2,X3,X4,X5,X6,X7,X8,X9]),
+    blocks(R1, R2, R3).

src/pyswip/examples/sudoku.py

@@ -0,0 +1,132 @@
+# -*- coding: utf-8 -*-
+
+# pyswip -- Python SWI-Prolog bridge
+# Copyright (c) 2007-2024 Yüce Tekol
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+import sys
+from typing import List, Union, Literal
+from io import StringIO
+
+from pyswip.prolog import Prolog
+
+
+__all__ = "Matrix", "solve"
+
+DIMENSION = 9
+
+
+Prolog.consult("sudoku.pl", relative_to=__file__)
+
+
+class Matrix:
+
+    def __init__(self, matrix: List[List[int]]) -> None:
+        if not matrix:
+            raise ValueError("matrix must be given")
+        if len(matrix) != DIMENSION:
+            raise ValueError("Matrix dimension must be 9")
+        self._dimension = len(matrix)
+        self._validate(self._dimension, matrix)
+        self.matrix = matrix
+
+    @classmethod
+    def from_text(cls, text: str) -> "Matrix":
+        lines = text.strip().split("\n")
+        dimension = len(lines)
+        rows = []
+        for i, line in enumerate(lines):
+            cols = line.split()
+            if len(cols) != dimension:
+                raise ValueError(f"All rows must have {dimension} columns, line {i+1} has {len(cols)}")
+            rows.append([0 if x == "." else int(x) for x in cols])
+        return cls(rows)
+
+    @classmethod
+    def _validate(cls, dimension: int, matrix: List[List[int]]):
+        if len(matrix) != dimension:
+            raise ValueError(f"Matrix must have {dimension} rows, it has {len(matrix)}")
+        for i, row in enumerate(matrix):
+            if len(row) != dimension:
+                raise ValueError(f"All rows must have {dimension} columns, row {i+1} has {len(row)}")
+
+    def __len__(self) -> int:
+        return self._dimension
+
+    def __str__(self) -> str:
+        sio = StringIO()
+        self.pretty_print(file=sio)
+        return sio.getvalue()
+
+    def __repr__(self) -> str:
+        return str(self.matrix)
+
+    def pretty_print(self, *, file=sys.stdout) -> None:
+        for row in self.matrix:
+            row = " ".join(str(x or ".") for x in row)
+            print(row, file=file)
+
+
+def solve(matrix: Matrix) -> Union[Matrix, Literal[False]]:
+    """
+    Solves the given Sudoku puzzle
+
+    Parameters:
+        matrix (Matrix): The matrix that contains the Sudoku puzzle
+
+    Returns:
+        Matrix: Solution matrix
+        False: If no solutions was found
+    """
+    p = repr(matrix).replace("0", "_")
+    result = list(Prolog.query(f"L={p},sudoku(L)", maxresult=1))
+    if not result:
+        return False
+    result = result[0].get("L")
+    if not result:
+        return False
+    return Matrix(result)
+
+
+def main():
+    puzzle = Matrix.from_text("""
+. 6 . 1 . 4 . 5 .
+. . 8 3 . 5 6 . .
+2 . . . . . . . 1
+8 . . 4 . 7 . . 6
+. . 6 . . . 3 . .
+7 . . 9 . 1 . . 4
+5 . . . . . . . 2
+. . 7 2 . 6 9 . .
+. 4 . 5 . 8 . 7 .
+""")
+    print("-- PUZZLE --")
+    puzzle.pretty_print()
+    print(" -- SOLUTION --")
+    solution = solve(puzzle)
+    if solution:
+        solution.pretty_print()
+        print(repr(solution))
+    else:
+        print("This puzzle has no solutions. Is it valid?")
+
+
+if __name__ == "__main__":
+    main()

tests/examples/test_sudoku.py

@@ -0,0 +1,55 @@
+import unittest
+
+from pyswip.examples.sudoku import Matrix, solve
+
+
+class MatrixTestCase(unittest.TestCase):
+
+    FIXTURE = """
+. 6 . 1 . 4 . 5 .
+. . 8 3 . 5 6 . .
+2 . . . . . . . 1
+8 . . 4 . 7 . . 6
+. . 6 . . . 3 . .
+7 . . 9 . 1 . . 4
+5 . . . . . . . 2
+. . 7 2 . 6 9 . .
+. 4 . 5 . 8 . 7 .
+    """
+
+    def test_matrix_from_text(self):
+        got = Matrix.from_text(self.FIXTURE)
+        target = [
+            [0, 6, 0, 1, 0, 4, 0, 5, 0],
+            [0, 0, 8, 3, 0, 5, 6, 0, 0],
+            [2, 0, 0, 0, 0, 0, 0, 0, 1],
+            [8, 0, 0, 4, 0, 7, 0, 0, 6],
+            [0, 0, 6, 0, 0, 0, 3, 0, 0],
+            [7, 0, 0, 9, 0, 1, 0, 0, 4],
+            [5, 0, 0, 0, 0, 0, 0, 0, 2],
+            [0, 0, 7, 2, 0, 6, 9, 0, 0],
+            [0, 4, 0, 5, 0, 8, 0, 7, 0],
+        ]
+        self.assertListEqual(target, got.matrix)
+
+    def test_solve_success(self):
+        puzzle = Matrix.from_text(self.FIXTURE)
+        solution = solve(puzzle)
+        target = [
+            [9, 6, 3, 1, 7, 4, 2, 5, 8],
+            [1, 7, 8, 3, 2, 5, 6, 4, 9],
+            [2, 5, 4, 6, 8, 9, 7, 3, 1],
+            [8, 2, 1, 4, 3, 7, 5, 9, 6],
+            [4, 9, 6, 8, 5, 2, 3, 1, 7],
+            [7, 3, 5, 9, 6, 1, 8, 2, 4],
+            [5, 8, 9, 7, 1, 3, 4, 6, 2],
+            [3, 1, 7, 2, 4, 6, 9, 8, 5],
+            [6, 4, 2, 5, 9, 8, 1, 7, 3],
+        ]
+        self.assertEqual(target, solution.matrix)
+
+    def test_solve_failure(self):
+        fixture = " 8" + self.FIXTURE[2:]
+        puzzle = Matrix.from_text(fixture)
+        solution = solve(puzzle)
+        self.assertFalse(solution)