feat: add flag FailureBehavior in Cast expression (#186)

substrait-io · May 13, 2022 · a3d3b2f · a3d3b2f
1 parent ff623df
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/proto/substrait/algebra.proto b/proto/substrait/algebra.proto
@@ -482,6 +482,13 @@ message Expression {
   message Cast {
     Type type = 1;
     Expression input = 2;
+    FailureBehavior failure_behavior = 3;
+
+    enum FailureBehavior {
+      FAILURE_BEHAVIOR_UNSPECIFIED = 0;
+      FAILURE_BEHAVIOR_RETURN_NULL = 1;
+      FAILURE_BEHAVIOR_THROW_EXCEPTION = 2;
+    }
   }
 
   message SwitchExpression {

diff --git a/site/docs/expressions/specialized_record_expressions.md b/site/docs/expressions/specialized_record_expressions.md
@@ -11,9 +11,7 @@ For each data type, it is possible to create a literal value for that data type.
 
 
 ## Cast Expression
-To convert a value from one type to another, Substrait defines a cast expression. Cast expression declare an expected type and an input argument.
-
-
+To convert a value from one type to another, Substrait defines a cast expression. Cast expressions declare an expected type, an input argument and an enumeration specifying failure behavior, indicating whether cast should return null on failure or throw an exception.
 
 ## If Expression
 An if value expression is an expression composed of one if clause, zero or more else if clauses and an else clause. In pseudocode, they are envisioned as: