| ▲ | cturtle 2 days ago |
| One of the new features I found interesting, declarations for global variables, is buried in the reference manual. Here's a link to the section that discusses it: https://www.lua.org/manual/5.5/manual.html#2.2 |
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| ▲ | HellsMaddy a day ago | parent | next [-] |
| Global-by-default scoping was one of Lua's largest mistakes. I wish they'd fix it, but of course it would break backwards compat. |
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| ▲ | drcxd 20 hours ago | parent | next [-] | | Strictly speaking, Lua is not global by default. All free names, that is, all names unqualified with `local`, is actually indexed from a table `_ENV`, which is set to `_G`, the global environment. So, all free names are effectively global by default, but you can change this behavior by put this line at the top of your file `local _G = _G; _ENV = {};`. This way, all free names are indexed from this new table, and all access to the global names must explicitly be accessed through `_G`, which is a local variable now. However, I have never seen such practice. Maybe it is just too complicated to accept that all free names are global variables and you have to explicitly make it local. | | |
| ▲ | Fwirt 17 hours ago | parent [-] | | Thanks to Lua’s great metaprogramming facilities, and the fact that _G is just a table, another workaround is to add a metamethod to _G that throws an error if you try to declare a global. That way you can still declare globals using rawset if you really want them, but it prevents you from declaring them accidentally in a function body. |
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| ▲ | kanbankaren 8 hours ago | parent | prev [-] | | yeah. I hate typing `local` for every variable. I would prefer they introduce some syntactic sugar like `let`(to mean local variable) and `const`(to mean local and constant). | | |
| ▲ | otikik 8 hours ago | parent [-] | | “local” is the same as the “let” that you are describing, isn’t it? Just 2 chars longer. |
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| ▲ | a day ago | parent | prev | next [-] |
| [deleted] |
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| ▲ | rhelz a day ago | parent | prev [-] |
| Why did you find this interesting? |
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| ▲ | kevin_thibedeau a day ago | parent | next [-] | | It indicates paving the path for local scoping in a future release where Lua 5 code is upgraded with global declarations to keep it working. | | | |
| ▲ | embedding-shape a day ago | parent | prev [-] | | For me it's interesting because global variable declarations haven't been needed before, so why now? Also, I'm not sure `global` was reserved before, but now it seems to be. | | |
| ▲ | TheCycoONE 10 hours ago | parent [-] | | lua does not preserve compatibility between minor versions. As such they don't need to reserve words for future use. |
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