luau-lang/luau
1
0
Fork 0
mirror of https://github.com/luau-lang/luau.git synced 2025-05-04 10:33:46 +01:00
Code Issues Projects Releases Packages Wiki Activity

Update compatibility.md

Browse source 
Add a note about Lua 5.3 change to semantics of __eq/__lt/__le metamethods.

We currently do not plan to implement this as this breaks backwards compatibility and makes these operators harder to reason about from the type checking perspective.

Fixes #1051.
This commit is contained in:
Arseny Kapoulkine 2023-10-03 07:08:31 -07:00 • committed by GitHub
parent 2a3a030341
commit 57511faa7d
Signed by: DevComp
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 2 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
docs/_pages/compatibility.md
View file

@ -92,7 +92,8 @@ Ephemeron tables may be implemented at some point since they do have valid uses
| new function `table.move` | ✔️ | | | new function `table.move` | ✔️ | |
| `collectgarbage("count")` now returns only one result | ✔️ | | | `collectgarbage("count")` now returns only one result | ✔️ | |
| `coroutine.isyieldable` | ✔️ | | | `coroutine.isyieldable` | ✔️ | |
| stricter error checking for `table.insert`/`table.remove` | 😞 | we love this, but it breaks compatibility | stricter error checking for `table.insert`/`table.remove` | 😞 | we love this, but it breaks compatibility |
| `__eq`/`__le`/`__lt` metamethods are called for unrelated metatables | ❌ | backwards compatibility and typechecking implications |
It's important to highlight integer support and bitwise operators. For Luau, it's rare that a full 64-bit integer type is necessary - double-precision types support integers up to 2^53 (in Lua which is used in embedded space, integers may be more appealing in environments without a native 64-bit FPU). However, there's a *lot* of value in having a single number type, both from performance perspective and for consistency. Notably, Lua doesn't handle integer overflow properly, so using integers also carries compatibility implications. It's important to highlight integer support and bitwise operators. For Luau, it's rare that a full 64-bit integer type is necessary - double-precision types support integers up to 2^53 (in Lua which is used in embedded space, integers may be more appealing in environments without a native 64-bit FPU). However, there's a *lot* of value in having a single number type, both from performance perspective and for consistency. Notably, Lua doesn't handle integer overflow properly, so using integers also carries compatibility implications.