jacques-n commented on a change in pull request #973: [CALCITE-2742] Update
USER and SYSTEM_USER to use DataContext for value
URL: https://github.com/apache/calcite/pull/973#discussion_r287147282
##########
File path:
core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java
##########
@@ -1069,6 +1139,117 @@ private void reduceCasts(RexCall outerCast) {
}
}
}
+
+ /**
+ * An immutable object capturing the set of options to be used for reducing
+ * expressions.
+ */
+ public static final class ReductionOptions {
+ private final boolean matchNullability;
+ private final boolean unknownAsFalse;
+ private final boolean treatDynamicCallsAsNonConstant;
+
+ private ReductionOptions(
+ boolean matchNullability,
+ boolean unknownAsFalse,
+ boolean treatDynamicCallsAsNonConstant) {
+ this.matchNullability = matchNullability;
+ this.unknownAsFalse = unknownAsFalse;
+ this.treatDynamicCallsAsNonConstant = treatDynamicCallsAsNonConstant;
+ }
+
+ /**
+ * Update the options to control dynamic treatment.
+ *
+ * @param treatDynamicCallsAsNonConstant Whether to treat dynamic
functions as
+ * non-constants (defaults to true)
+ * @return A new set of ReductionOptions
+ */
+ public ReductionOptions treatDynamicCallsAsNonConstant(
+ boolean treatDynamicCallsAsNonConstant) {
+ return new ReductionOptions(
+ this.matchNullability,
+ this.unknownAsFalse,
+ treatDynamicCallsAsNonConstant);
+ }
+
+ /**
+ * <p> Update the options to control nullability matching.
+ *
+ * <p>The {@code matchNullability} flag comes into play when reducing a
+ * expression whose type is nullable. Suppose we are reducing an expression
+ * {@code CASE WHEN 'a' = 'a' THEN 1 ELSE NULL END}. Before reduction the
+ * type is {@code INTEGER} (nullable), but after reduction the literal 1
has
+ * type {@code INTEGER NOT NULL}.
+ *
+ * <p>In some situations it is more important to preserve types; in this
Review comment:
This functionality and comment already existed. This patch simply moved the
comment. If you think this should be improved I suggest that you open a ticket
to address separately.
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