Reorganized examples

README.md

@@ -37,11 +37,10 @@ Thanks to all [contributors](CONTRIBUTORS.txt).
 
 ```python
 from pyswip import Prolog
-prolog = Prolog()
-prolog.assertz("father(michael,john)")
-prolog.assertz("father(michael,gina)")
-list(prolog.query("father(michael,X)")) == [{'X': 'john'}, {'X': 'gina'}]
-for soln in prolog.query("father(X,Y)"):
+Prolog.assertz("father(michael,john)")
+Prolog.assertz("father(michael,gina)")
+list(Prolog.query("father(michael,X)")) == [{'X': 'john'}, {'X': 'gina'}]
+for soln in Prolog.query("father(X,Y)"):
     print(soln["X"], "is the father of", soln["Y"])
 # michael is the father of john
 # michael is the father of gina
@@ -52,8 +51,7 @@ Assuming the filename "knowledge_base.pl" and the Python is being run in the sam
 
 ```python
 from pyswip import Prolog
-prolog = Prolog()
-prolog.consult("knowledge_base.pl")
+Prolog.consult("knowledge_base.pl")
 ```
 
 ### Foreign Functions
@@ -67,10 +65,9 @@ hello.arity = 1
 
 registerForeign(hello)
 
-prolog = Prolog()
-prolog.assertz("father(michael,john)")
-prolog.assertz("father(michael,gina)")
-print(list(prolog.query("father(michael,X), hello(X)")))
+Prolog.assertz("father(michael,john)")
+Prolog.assertz("father(michael,gina)")
+print(list(Prolog.query("father(michael,X), hello(X)")))
 ```
 
 ### Pythonic interface (Experimental)

examples/coins/coins.py

@@ -25,17 +25,16 @@
 
 
 def main():
-    prolog = Prolog()
-    prolog.consult("coins.pl", relative_to=__file__)
+    Prolog.consult("coins.pl", relative_to=__file__)
     count = int(input("How many coins (default: 100)? ") or 100)
     total = int(input("What should be the total (default: 500)? ") or 500)
-    for i, soln in enumerate(prolog.query("coins(S, %d, %d)." % (count, total))):
+    for i, soln in enumerate(Prolog.query("coins(S, %d, %d)." % (count, total))):
         S = zip(soln["S"], [1, 5, 10, 50, 100])
         print(i, end=" ")
         for c, v in S:
             print(f"{c}x{v}", end=" ")
         print()
-    list(prolog.query(f"coins(S, {count}, {total})."))
+    list(Prolog.query(f"coins(S, {count}, {total})."))
 
 
 if __name__ == "__main__":

examples/coins/coins_new.py

@@ -25,8 +25,7 @@
 
 
 def main():
-    prolog = Prolog()
-    prolog.consult("coins.pl", relative_to=__file__)
+    Prolog.consult("coins.pl", relative_to=__file__)
     count = int(input("How many coins (default: 100)? ") or 100)
     total = int(input("What should be the total (default: 500)? ") or 500)
     coins = Functor("coins", 3)

examples/create_term.py

@@ -26,8 +26,6 @@
 
 
 def main():
-    prolog = Prolog()
-
     a1 = PL_new_term_refs(2)
     a2 = a1 + 1
     t = PL_new_term_ref()
@@ -42,7 +40,7 @@ def main():
     PL_cons_functor_v(ta, assertz, t)
     PL_call(ta, None)
 
-    print(list(prolog.query("animal(X,Y)", catcherrors=True)))
+    print(list(Prolog.query("animal(X,Y)", catcherrors=True)))
 
 
 if __name__ == "__main__":

examples/draughts/puzzle1.py

@@ -37,10 +37,9 @@
 
 
 def main():
-    prolog = Prolog()
-    prolog.consult("puzzle1.pl", relative_to=__file__)
+    Prolog.consult("puzzle1.pl", relative_to=__file__)
 
-    for soln in prolog.query("solve(B)."):
+    for soln in Prolog.query("solve(B)."):
         B = soln["B"]
 
         # [NW,N,NE,W,E,SW,S,SE]

examples/father.py

@@ -25,14 +25,12 @@
 
 
 def main():
-    p = Prolog()
-
     father = Functor("father", 2)
     mother = Functor("mother", 2)
 
-    p.assertz("father(john,mich)")
-    p.assertz("father(john,gina)")
-    p.assertz("mother(jane,mich)")
+    Prolog.assertz("father(john,mich)")
+    Prolog.assertz("father(john,gina)")
+    Prolog.assertz("mother(jane,mich)")
 
     Y = Variable()
     Z = Variable()
@@ -46,7 +44,7 @@ def main():
     q.closeQuery()  # Newer versions of SWI-Prolog do not allow nested queries
 
     print("\nQuery with strings\n")
-    for s in p.query("father(john,Y),mother(Z,Y)"):
+    for s in Prolog.query("father(john,Y),mother(Z,Y)"):
         print(s["Y"], s["Z"])
 
 

examples/hanoi/hanoi.py

@@ -76,12 +76,11 @@ def draw(self):
 
 def main():
     n = 3
-    prolog = Prolog()
     tower = Tower(n, True)
     notifier = Notifier(tower.move)
     registerForeign(notifier.notify)
-    prolog.consult("hanoi.pl", relative_to=__file__)
-    list(prolog.query("hanoi(%d)" % n))
+    Prolog.consult("hanoi.pl", relative_to=__file__)
+    list(Prolog.query("hanoi(%d)" % n))
 
 
 if __name__ == "__main__":

examples/hanoi/hanoi_simple.py

@@ -31,10 +31,9 @@ def notify(t):
 
     notify.arity = 1
 
-    prolog = Prolog()
     registerForeign(notify)
-    prolog.consult("hanoi.pl", relative_to=__file__)
-    list(prolog.query(f"hanoi({N})"))
+    Prolog.consult("hanoi.pl", relative_to=__file__)
+    list(Prolog.query(f"hanoi({N})"))
 
 
 if __name__ == "__main__":

examples/register_foreign.py

@@ -33,6 +33,5 @@ def atom_checksum(*a):
         return False
 
 
-p = Prolog()
 registerForeign(atom_checksum, arity=2)
-print(list(p.query("X='Python', atom_checksum(X, Y)", catcherrors=False)))
+print(list(Prolog.query("X='Python', atom_checksum(X, Y)", catcherrors=False)))

examples/register_foreign_simple.py

@@ -36,10 +36,9 @@ def hello(t):
 
 def main():
     registerForeign(hello)
-    prolog = Prolog()
-    prolog.assertz("father(michael,john)")
-    prolog.assertz("father(michael,gina)")
-    list(prolog.query("father(michael,X), hello(X)"))
+    Prolog.assertz("father(michael,john)")
+    Prolog.assertz("father(michael,gina)")
+    list(Prolog.query("father(michael,X), hello(X)"))
 
 
 if __name__ == "__main__":

examples/sendmoremoney/money.py

@@ -30,9 +30,8 @@
 from pyswip import Prolog
 
 letters = list("SENDMORY")
-prolog = Prolog()
-prolog.consult("money.pl", relative_to=__file__)
-for result in prolog.query("sendmore(X)"):
+Prolog.consult("money.pl", relative_to=__file__)
+for result in Prolog.query("sendmore(X)"):
     r = result["X"]
     for i, letter in enumerate(letters):
         print(letter, "=", r[i])

examples/sendmoremoney/money_new.py

@@ -32,9 +32,8 @@
 
 def main():
     letters = list("SENDMORY")
-    prolog = Prolog()
     sendmore = Functor("sendmore")
-    prolog.consult("money.pl", relative_to=__file__)
+    Prolog.consult("money.pl", relative_to=__file__)
 
     X = Variable()
     call(sendmore(X))

examples/sudoku/sudoku.py

@@ -59,9 +59,9 @@ def pretty_print(table):
 
 
 def solve(problem):
-    prolog.consult("sudoku.pl", relative_to=__file__)
+    Prolog.consult("sudoku.pl", relative_to=__file__)
     p = str(problem).replace("0", "_")
-    result = list(prolog.query("L=%s,sudoku(L)" % p, maxresult=1))
+    result = list(Prolog.query("L=%s,sudoku(L)" % p, maxresult=1))
     if result:
         result = result[0]
         return result["L"]
@@ -83,5 +83,4 @@ def main():
 
 
 if __name__ == "__main__":
-    prolog = Prolog()
     main()

examples/sudoku/sudoku_daily.py

@@ -72,9 +72,9 @@ def get_daily_sudoku(url):
 
 
 def solve(problem):
-    prolog.consult("sudoku.pl", relative_to=__file__)
+    Prolog.consult("sudoku.pl", relative_to=__file__)
     p = str(problem).replace("0", "_")
-    result = list(prolog.query("Puzzle=%s,sudoku(Puzzle)" % p, maxresult=1))
+    result = list(Prolog.query(f"Puzzle={p},sudoku(Puzzle)", maxresult=1))
     if result:
         result = result[0]
         return result["Puzzle"]
@@ -83,9 +83,8 @@ def solve(problem):
 
 
 if __name__ == "__main__":
-    URL = "http://www.sudoku.org.uk/daily.asp"
+    URL = "https://www.sudoku.org.uk/daily.asp"
 
-    prolog = Prolog()  # having this in `solve` bites! because of __del__
     print("Getting puzzle from:", URL)
     puzzle = get_daily_sudoku(URL)
     print("-- PUZZLE --")

src/pyswip/examples/sudoku.py

@@ -28,20 +28,21 @@
 from pyswip.prolog import Prolog
 
 
-__all__ = "Matrix", "solve"
+__all__ = "Matrix", "solve", "prolog_source"
 
-DIMENSION = 9
+_DIMENSION = 9
+_SOURCE_PATH = "sudoku.pl"
 
 
-Prolog.consult("sudoku.pl", relative_to=__file__)
+Prolog.consult(_SOURCE_PATH, 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:
+        if len(matrix) != _DIMENSION:
             raise ValueError("Matrix dimension must be 9")
         self._dimension = len(matrix)
         self._validate(self._dimension, matrix)
@@ -105,6 +106,13 @@ def solve(matrix: Matrix) -> Union[Matrix, Literal[False]]:
     return Matrix(result)
 
 
+def prolog_source() -> str:
+    from pathlib import Path
+    path = Path(__file__).parent / _SOURCE_PATH
+    with open(path) as f:
+        return f.read()
+
+
 def main():
     puzzle = Matrix.from_text("""
 . 6 . 1 . 4 . 5 .
@@ -123,7 +131,6 @@ def main():
     solution = solve(puzzle)
     if solution:
         solution.pretty_print()
-        print(repr(solution))
     else:
         print("This puzzle has no solutions. Is it valid?")
 

src/pyswip/prolog.py

@@ -218,14 +218,13 @@ def query(cls, query, maxresult=-1, catcherrors=True, normalize=True):
         If the query is a yes/no question, returns {} for yes, and nothing for no.
         Otherwise returns a generator of dicts with variables as keys.
 
-        >>> prolog = Prolog()
-        >>> prolog.assertz("father(michael,john)")
-        >>> prolog.assertz("father(michael,gina)")
-        >>> bool(list(prolog.query("father(michael,john)")))
+        >>> Prolog.assertz("father(michael,john)")
+        >>> Prolog.assertz("father(michael,gina)")
+        >>> bool(list(Prolog.query("father(michael,john)")))
         True
-        >>> bool(list(prolog.query("father(michael,olivia)")))
+        >>> bool(list(Prolog.query("father(michael,olivia)")))
         False
-        >>> print sorted(prolog.query("father(michael,X)"))
+        >>> print sorted(Prolog.query("father(michael,X)"))
         [{'X': 'gina'}, {'X': 'john'}]
         """
         return cls._QueryWrapper()(query, maxresult, catcherrors, normalize)

tests/examples/test_sudoku.py

@@ -1,6 +1,6 @@
 import unittest
 
-from pyswip.examples.sudoku import Matrix, solve
+from pyswip.examples.sudoku import Matrix, solve, prolog_source
 
 
 class MatrixTestCase(unittest.TestCase):
@@ -53,3 +53,7 @@ def test_solve_failure(self):
         puzzle = Matrix.from_text(fixture)
         solution = solve(puzzle)
         self.assertFalse(solution)
+
+    def test_prolog_source(self):
+        text = prolog_source()
+        self.assertIn("Prolog Sudoku Solver", text)