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docs: More emoji tweaks 

Also move \u to Lua 5.3
This commit is contained in:
Arseny Kapoulkine 2020-06-11 20:35:10 -07:00
parent 6424d84bc3
commit 1c91ca1f2d
1 changed files with 7 additions and 6 deletions
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13
docs/compatibility.md
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@ -7,7 +7,7 @@ Our overall goal is to incorporate features from the later versions of Lua when
- ✔️ - the feature is available in Luau
- ❌ - the feature is not available in Luau because we don't believe it makes sense to include it
- ⁉️ - the feature is not available in Luau because of compatibility/sandboxing concerns
- 😞 - the feature is not available in Luau because of compatibility/sandboxing concerns
- 🔜 - the feature is not available in Luau yet but we'd like to include it and are possibly working on it
- 🤷‍♀️ - the feature is not available in Luau yet; we don't have strong opinions on it so it might make it at some point
@ -36,9 +36,9 @@ Lua 5.2
| emergency garbage collector | ❌ | Luau runs in environments where handling memory exhaustion in emergency situations is not tenable |
| goto statement | ❌ | this complicates the compiler due to handling of locals and doesn't address a significant need |
| finalizers for tables | ❌ | no `__gc` support due to sandboxing and performance/complexity |
| no more fenv for threads or functions | ⁉️ | we love this, but it breaks compatibility |
| no more fenv for threads or functions | 😞 | we love this, but it breaks compatibility |
| tables honor the `__len` metamethod | ❌ | performance implications, no strong use cases
| hex and `\z` escapes in strings (also `\u` for Unicode) | ✔️ | |
| hex and `\z` escapes in strings | ✔️ | |
| support for hexadecimal floats | 🤷‍♀️ | no strong use cases |
| order metamethods work for different types | ❌ | no strong use cases and more complicated semantics + compat |
| empty statement | ✔️ | |
@ -61,6 +61,7 @@ Lua 5.3
| feature | status | notes |
|---------|--------|------|
| `\u` escapes in strings | ✔️ | |
| integers (64-bit by default) | ❌ | backwards compatibility and performance implications |
| bitwise operators | ❌ | `bit32` library covers this |
| basic utf-8 support | ✔️ | we include `utf8` library and other UTF8 features |
@ -88,13 +89,13 @@ Lua 5.4
| new implementation for math.random | ✔️ | our RNG is based on PCG, unlike Lua 5.4 which uses Xoroshiro |
| optional `init` argument to `string.gmatch` | 🤷‍♀️ | no strong use cases |
| new functions `lua_resetthread` and `coroutine.close` | ❌ | not useful without to-be-closed variables |
| coersions string-to-number moved to the string library | ⁉️ | we love this, but it breaks compatibility |
| coersions string-to-number moved to the string library | 😞 | we love this, but it breaks compatibility |
| new format `%p` in `string.format` | 🤷‍♀️ | no strong use cases |
| `utf8` library accepts codepoints up to 2^31 | 🤷‍♀️ | no strong use cases |
| The use of the `__lt` metamethod to emulate `__le` has been removed | ⁉️ | breaks compatibility and doesn't seem very interesting otherwise |
| The use of the `__lt` metamethod to emulate `__le` has been removed | 😞 | breaks compatibility and doesn't seem very interesting otherwise |
| When finalizing objects, Lua will call `__gc` metamethods that are not functions | ❌ | no `__gc` support due to sandboxing and performance/complexity |
| The function print calls `__tostring` instead of tostring to format its arguments. | 🔜 | |
| By default, the decoding functions in the utf8 library do not accept surrogates. | ⁉️ | breaks compatibility and doesn't seem very interesting otherwise |
| By default, the decoding functions in the utf8 library do not accept surrogates. | 😞 | breaks compatibility and doesn't seem very interesting otherwise |
Lua has a beautiful syntax and frankly we're disappointed in the `<const>`/`<toclose>` which takes away from that beauty. Taking syntax aside, `<toclose>` isn't very useful in Luau - its dominant use case is for code that works with external resources like files or sockets, but we don't provide such APIs - and has a very large complexity cost, evidences by a lot of bug fixes since the initial implementation in 5.4 work versions. `<const>` in Luau doesn't matter for performance - our multi-pass compiler is already able to analyze the usage of the variable to know if it's modified or not and extract all performance gains from it - so the only use here is for code readability, where the `<const>` syntax is... suboptimal.