zabetak commented on a change in pull request #1029: [CALCITE-2824] Fix invalid
usage of RexExecutorImpl
URL: https://github.com/apache/calcite/pull/1029#discussion_r261560347
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File path: core/src/main/java/org/apache/calcite/rex/RexExecutor.java
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@@ -32,6 +34,22 @@
* @param reducedValues List to which reduced expressions are appended
*/
void reduce(RexBuilder rexBuilder, List<RexNode> constExps, List<RexNode>
reducedValues);
+
+ /**
+ * Checks if condition first implies (⇒) condition second.
+ *
+ * <p>This reduces to SAT problem which is NP-Complete.
+ * When this method says first implies second then it is definitely true.
+ * But it cannot prove that first does not imply second.
+ *
+ * @param rexBuilder Rex builder
+ * @param rowType row type
+ * @param first first condition
+ * @param second second condition
+ * @return true if it can prove first ⇒ second; otherwise false i.e.,
+ * it doesn't know if implication holds
+ */
+ boolean implies(RexBuilder rexBuilder, RelDataType rowType, RexNode first,
RexNode second);
Review comment:
I am not in favor of adding this method in the RexExecutor interface. Many
similar methods exist in RexImplicationChecker which is already public API.
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