1.5 KiB
null-conditional await
- Proposed
- Prototype: None
- Implementation: None
- Specification: Started, below
Summary
Support an expression of the form await? e, which awaits e if it is non-null, otherwise it results in null.
Motivation
This is a common coding pattern, and this feature would have nice synergy with the existing null-propagating and null-coalescing operators.
Detailed design
We add a new form of the await_expression:
await_expression
: 'await' '?' unary_expression
;
The null-conditional await operator awaits its operand only if that operand is non-null. Otherwise the result of applying the operator is null.
The type of the result is computed using the rules for the null-conditional operator.
Drawbacks
As with any language feature, we must question whether the additional complexity to the language is repaid in the additional clarity offered to the body of C# programs that would benefit from the feature.
Alternatives
Although it requires some boilerplate code, uses of this operator can often be replaced by an expression something like (e == null) ? null : await e or a statement like if (e != null) await e.
Unresolved questions
- Requires LDM review
Design meetings
None.