Re: require() parse error in 5.3.4/5.4.0-work2?

[Thijs Schreijer <thijs@...>]

> On 27 Jun 2018, at 13:15, Kenneth Lorber <keni@his.com> wrote:
> 
>> On 26 Jun 2018, at 13:13, Kenneth Lorber <keni@his.com<mailto:keni@his.com>> wrote:
>> 
>> On Jun 23, 2018, at 8:57 AM, Andrew Gierth <andrew@tao11.riddles.org.uk<mailto:andrew@tao11.riddles.org.uk>> wrote:
>> 
>> [...]
>> To me it is about flexibility, multiple return values, and the ability to only take what is needed. Eg:
>> 
>>   take_two(return_three())
>> 
>> Without a bunch of locals. Why would you even want to limit that and make it an error? It takes flexibility away.
>> 
>> For example: take OpenResty, it uses a lot of those extra checks and it's a pita. See this code for example:
>> 
>> https://github.com/Kong/kong/blob/82a51c4b519728eed4f957fdaa547ed4abea9332/kong/globalpatches.lua#L296-L302
>> 
>> The last argument “socket options” must be a table, not even `nil` is accepted. Hence in the calling code it requires an if-then construct.
>> 
>> So be careful what you wish for with those checks.
>> 
>> Thijs
> 
> I was going to just let this go, but the replies are getting so far afield I just can't.  I'm not asking about the language feature in general, or about function prototypes, or  user written code or any of the other things people have brought up.
> 
> I'm talking about the basic, lua-distribution-supplied functions such as require.  So let me rephrase my original questions and we'll just stick to require only:
> 
> Is there some reason accepting     require("file", "ignored argument")     is a language feature?  Some use-case I don't see?  (If so, why is there the occasional check for extra arguments?)
> 
> Is it documented somewhere I missed that lua functions supplied by the distribution accept and ignore extra arguments?
> 
> Is there any reason not to add checks for extra arguments to the functions supplied by the lua distribution?  If it's performance, it could be available as a compile time option.
> 
> I hope this gets the discussion back on track, whether anyone agrees with me or not.
> 
> Thanks,
> Keni

The way I see it, Lua tries to be as “unspecific” as possible, as in that the global environment itself is just a table for example, as are all libraries, and the registry, and every global can be redefined by a Lua version.

In your example `require` is just a function, as any other Lua function. With your proposal you’re defining “Lua defined functions” and “language defined functions” as separate types/behaviours. Why this complication?

Thijs