From 28b02084370ff7760f9d2fb21db36fc8d028ca31 Mon Sep 17 00:00:00 2001 From: Vyacheslav Egorov <vegorov@roblox.com> Date: Wed, 9 Jun 2021 14:52:16 +0300 Subject: [PATCH] Remove section on 'safe navigation operator', it's not an alternative Remove 'Alternatives' section as it is empty. --- rfcs/syntax-nil-forgiving-operator.md | 19 ------------------- 1 file changed, 19 deletions(-) diff --git a/rfcs/syntax-nil-forgiving-operator.md b/rfcs/syntax-nil-forgiving-operator.md index 7784ee17..774d3b6a 100644 --- a/rfcs/syntax-nil-forgiving-operator.md +++ b/rfcs/syntax-nil-forgiving-operator.md @@ -65,22 +65,3 @@ Another case is for constants, but the check will require an AST match: local a = 2! local b = "str"! ``` - -## Alternatives - -It might be useful to consider a safe navigation operator (also known as null-chaining and optional chaining operator) as an addition to this proposal. - -We can call it a nil-chaining operator. - -Compared to nil-forgiving operator, nil-chaining operator does impact the run-time behavior. - -It makes it possible to avoid a run-time error of accessing `nil` values by replacing the result of the expression with `nil` instead of evaluation the part on RHS of the operator. - -Because nil-chaining has a run-time check it can only be used in specific expression kinds because it changes how each one of them is evaluated. - -Multiple cases will be defined: -* ?. nil-chaining member access operator. If LHS is `nil`, member access is not performed and the expression value is `nil`. The type of this expressions is a union between member type and `nil`. -* ?[] nil-chaining indexing operator. If LHS is `nil`, index access is not performed and the expression value is `nil`. Type of the expression is a union between element type and `nil`. -* ?() nil-chaining function call operator. If LHS is `nil`, function is not called and the expression value is `nil`. Type of the expression is a union between function return type and `nil`. - -nil-chaining operator can be found in many programming languages, including C#, Dart, Kotlin, Swift and TypeScript.