python

packages/swig/python/yapex.py

@@ -0,0 +1,50 @@
+# python commands
+
+import sys
+import yap
+
+#
+# initialize engine
+engine = yap.YAPEngine();
+# engine = yap.YAPEngine(yap.YAPParams());
+
+def query( s ):
+    q = engine.query(s)
+    while q.next():
+        vs = q.namedVars()
+        if vs.length() == 0:
+            print( "yes" )
+            return
+        else:
+            while vs.length() > 0:
+                eq = vs.car()
+                print( eq.getArg(1).text() + " = " + eq.getArg(2).text() )
+                vs = vs.cdr()
+            if q.deterministic():
+                return
+            s = input("next: ?")
+            if s.find(';') != 0 :
+                return
+    print( "no more answers" )
+    return
+
+def live():
+    loop = True
+    while loop:
+        try:
+            s = input("?- ")
+            query( s )
+        except SyntaxError as err:
+            print("Syntax Error error: {0}".format(err))
+        except EOFError:
+            return
+        except RuntimeError as err:
+            print("YAP Execution Error: {0}".format(err))
+        except ValueError:
+            print("Could not convert data to an integer.")
+        except:
+            print("Unexpected error:", sys.exc_info()[0])
+            raise
+
+
+live()