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

Note on alternative token

Browse source
This commit is contained in:
Vyacheslav Egorov 2021-06-09 16:37:33 +03:00
parent 6b9427008e
commit 21b42f161a
1 changed files with 7 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
rfcs/syntax-lambda-function-expressions.md
View file

@ -65,7 +65,7 @@ When we are done with parsing, we re-use the existing AST for function expressio
### Single return value
In Luau, multiple return value support is a first-class citizen, but the syntax becomes ambiguous if we allow that:
```lua
f(a, b -> b.a, b.b, c) -- how many values does the b return or the f accept?
f(a, b -> b.a, b.b, c) -- how many values does the lambda return or the 'f' accepts?
```
As a solution, regular anonymous function definition can be used when multiple return values are required.
@ -96,3 +96,9 @@ The problem with this option is that parsing with limited look-ahead and without
f((x):number(2))
```
Only after the return type annotation can we see that there is no `->` token and this was a member function call.
### Use new `=>` token instead of `->`
`->` token is already used for return type in function type annotations.
While there might be value of using a different token (and some programming languages do use `=>`), it introduces a new token when it's not necessary.