Make propositional implication to always be available.

integration_tests/propositional_implication_test.l

@@ -0,0 +1,34 @@
+#
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Testing propositional implication.
+
+Bird("duck");
+Bird("sparrow");
+
+Animal("dog");
+
+Dragon("wyvern");
+
+Flies("duck");
+Flies("sparrow");
+Flies("wyvern");
+
+WhoFiles("animal") :- Animal(x) => Flies(x);
+WhoFiles("bird") :- Bird(x) => Flies(x);
+WhoFiles("dragon") :- Dragon(x) => Flies(x);
+
+@OrderBy(Test, "col0");
+Test(x) :- WhoFiles(x);

integration_tests/propositional_implication_test.txt

@@ -0,0 +1,6 @@
++--------+
+| col0   |
++--------+
+| bird   |
+| dragon |
++--------+

integration_tests/run_tests.py

@@ -65,6 +65,8 @@ def RunAll(test_presto=False, test_trino=False):
     RunTest("dialects/trino/joins_test")
     RunTest("dialects/trino/joins_test")
 
+  RunTest("propositional_implication_test")
+
   RunTest("duckdb_negation_test")
   RunTest("duckdb_is_default")
 

parser_py/parse.py

@@ -942,9 +942,9 @@ def ParseProposition(s):
     c = ParsePropositionalEquivalence(s)
     if c:
       return {'conjunction': {'conjunct': [c]}}
-    c = ParsePropositionalImplication(s)
-    if c:
-      return {'conjunction': {'conjunct': [c]}}
+  c = ParsePropositionalImplication(s)
+  if c:
+    return {'conjunction': {'conjunct': [c]}}
 
   c = ParseImplication(s)
   if c: