fix: address comments

proto/substrait/algebra.proto

@@ -482,12 +482,11 @@ message Expression {
   message Cast {
     Type type = 1;
     Expression input = 2;
-    CastFailureBehavior failure_behavior = 3;
+    FailureBehavior failure_behavior = 3;
 
-    enum CastFailureBehavior {
-      CONDITION_FLAG_UNSPECIFIED = 0;
-      CONDITION_FLAG_NULL_ON_FAILURE = 1;
-      CONDITION_FLAG_THROW_ON_FAILURE = 2;
+    enum FailureBehavior {
+      FAILURE_BEHAVIOR_THROW_EXCEPTION = 0;
+      FAILURE_BEHAVIOR_RETURN_NULL = 1;
     }
   }
 

site/docs/expressions/specialized_record_expressions.md

@@ -11,8 +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. A Cast expression declares an expected type, an input argument and an argument specifying whether the operation should throw or return null on failure.
-
+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: