luau-lang/luau
1
0
Fork 0
mirror of https://github.com/luau-lang/luau.git synced 2025-04-04 10:50:54 +01:00
Code Issues Projects Releases Packages Wiki Activity

Remove section on 'safe navigation operator', it's not an alternative

Browse source 
Remove 'Alternatives' section as it is empty.
This commit is contained in:
Vyacheslav Egorov 2021-06-09 14:52:16 +03:00
parent f02ba60bfa
commit 28b0208437
1 changed files with 0 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
rfcs/syntax-nil-forgiving-operator.md
View file

@ -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.