Unclear grammar for global in 5.5

[Sergey Bronnikov]

Hello,

Lua 5.5 BNF grammar contains rules for "local" and "global" names:

stat ::=  ‘;’ |
<snipped>
 local attnamelist [‘=’ explist] |
 global attnamelist |

<snipped>

I'm confused by the absence of the "[‘=’ explist]" in the rule for "global".

It seems that the code below is syntactically incorrect:

global a, b = 1, 2

or 

global a = 1

or

global <const> a = 1

However, the chunks above are successfully accepted by Lua:

$ ./lua -e "global a, b = 1, 2"; echo $?
0
$ ./lua -e "global a = 1"; echo $?
0
$ ./lua -e "global <const> a = 1"; echo $?
0

Where is a truth?

Also, it is suspicious that chunk below does not work:

$ ./lua -e "global a; print()"
./lua: (command line):1: variable 'print' not declared

The same with "local" works fine:

$ ./lua -e "local a; print()"; echo $?
0

Version: PUC Rio Lua 5.5, 84938a7d2b680d2d28ec99606e84fe712efd9a69

1. https://www.lua.org/manual/5.5/manual.html#9

[Luiz Henrique de Figueiredo]

> I'm confused by the absence of the "[‘=’ explist]" in the rule for "global".

This has been fixed in Lua 5.5.1. See
https://www.lua.org/work/doc/manual.html#9

[Sergey Bronnikov]

Thanks!

Is it a bug?

$ ./lua -e "global a; print()"
./lua: (command line):1: variable 'print' not declared

Sergey

 

[Roberto Ierusalimschy]

> $ ./lua -e "global a; print()"
> ./lua: (command line):1: variable 'print' not declared

Please read the manual:

"outside any global declaration, Lua works as global-by-default.
Inside any global declaration, Lua works without a default: All
variables must be declared."

-- Roberto