Re: Putting version information, description, copright into modules

[Marc Balmer <marc@...>]

> Am 13.02.2016 um 14:23 schrieb Philipp Janda <siffiejoe@gmx.net>:
> 
> Am 12.02.2016 um 18:36 schröbte Peter Aronoff:
>> Philipp Janda wrote:
>>> I'm sure we all agree that a general table should be able to hold any
>>> string key including ones starting with _ + uppercase letter. However,
>>> a module table is not a general table, and there already has been Lua-Rio
>>> code in Lua 5.1 that used the `_M`, `_NAME`, and `_PACKAGE` fields in
>>> module tables, so the reservation of those names probably does not apply
>>> to global variables (and the registry) only.
>> 
>> But those tables and the tables that my module exports are by definition
>> distinct, aren't they? I'm worried that I'm missing something painfully
>> obvious, but I don't see how a clash could occur.
> 
> I just wanted to mention that there is official code out there that sets fields with reserved names in module tables. At the moment there will be no clash, because `module` is deprecated (5.2) or gone (5.3), and it didn't set `_VERSION` anyway. But I take that as a hint that you use reserved names in module tables at your own risk.
> 
>> A user of my module has
>> to require the module and save the table it returns, using an identifier.
>> That identifier holds one specific table and is distinct from any other
>> table from Lua-Rio or any other code.
>> 
>> More concretely:
>> 
>> 	local split = require('split')
>> 	if split._VERSION == 'whatever' then
>> 		whatever()
>> 	else
>> 		whatever_else()
>> 	end
>> 
>> How can the _VERSION identifier in the one table ever clash with one in
>> another table?
> 
> It won't clash with fields in other tables, but it could clash with future Lua code, because as suggested by the implementation of the `module` function `_VERSION` is a reserved name in module tables.
> 
> While we are talking standardization:
> 1) LPeg (which I consider semi-official) has a `version()` function.
> 2) Is a string (especially if it also contains non-version info like the package name) really the most useful representation for a module version? Should we maybe make the semver module[1] the most often used dependency in the LuaRocks universe?
> 

Where did you find that reference?