Re: string literal following by colon-style call?

On Sat, Aug 10, 2013 at 5:50 AM, Lorenzo Donati <lorenzodonatibz@tiscali.it> wrote:

On 10/08/2013 9.42, Hao Wu wrote:
>
>
>
> On Sat, Aug 10, 2013 at 12:35 AM, Tim Hill <drtimhill@gmail.com

> <mailto:drtimhill@gmail.com>> wrote:
>
>
> On Aug 10, 2013, at 12:31 AM, Tim Hill <drtimhill@gmail.com

> <mailto:drtimhill@gmail.com>> wrote:
>
>>
>> On Aug 9, 2013, at 11:58 PM, Hao Wu <wuhao.wise@gmail.com

>> <mailto:wuhao.wise@gmail.com>> wrote:
>>
>>>
>>> So my question is, when dealing with string literal, why couldn't
>>> we just say:
>>>
>>> "a string literal":lower()
>>>
>>> instead
>>>
>>> ("a string literal"):lower()
>>>
>>> Is there a language reason to prevent this?
>>>
>>> Thanks,
>>>
>>> ~hao
>>
>> What's more interesting is that, by my reading of the BNF,
>> _neither_ of these should work (though the second, as you state,
>> does work). SO far as I can see, the BNF doesn't describe the full
>> colon syntax (it is only mentioned when used as part of a function
>> declaration).
>>
>> --Tim
>>
>
> Ignore that .. my brain shut down there for a moment. Here is the
> Lua BNF that is significant:
>
> prefixexp ::= var | functioncall | ‘(’ exp ‘)’ functioncall ::=
> prefixexp args | prefixexp ‘:’ Name args
>
> So yes, you do need parens.
>
>
> Yes, I was about to say that.
>
> It certainly shouldn't be a "BNF" issue or "parser" issue that wouldn't
> accept the first form (or maybe it is? the parser would take more
> memory? but we also have byte-code...) - this made me wonder why and the
> real reason behind it
>
>
> --Tim
>
>
>
>
> ~hao

There have been already discussions on this (check old posts ~ 2 years
ago if my memory isn't failing me).

IIRC the parens are needed to avoid some ambiguity in parsing.

Now I get it:

foo"str".attr1

would be translated in two different ways. so basically function call is prior to indexing in Lua.

so if I understand correctly:

- literals that starts with non-parenthesis (quote and curly bracket) being an alternative to parenthesis to a function call (pun intended)

- indexing meant to be for "variables" not literals

(I guess I was so used to indexing being the highest operator).

-- Lorenzo

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