Re: Language Versions

[Akim Demaille]

Hi Arthur,

> Le 6 sept. 2022 à 23:05, Arthur Schwarz <home@slipbits.com> a écrit :
> 
> Hi Akim;
> 
> I do mean the version of C/C++/D/Java should be stated.

It does make sense.

> For example int he C case there is the K & R version.

We aim at C90.  KnR support was dropped long ago:

> * Noteworthy changes in release 2.6 (2012-07-19) [stable]
> 
> ** Future changes
> 
>   The next major release of Bison will drop support for the following
>   deprecated features.  Please report disagreements to bug-bison@gnu.org.
> 
> *** K&R C parsers
> 
>   Support for generating parsers in K&R C will be removed.  Parsers
>   generated for C support ISO C90, and are tested with ISO C99 and ISO C11
>   compilers.

And I can't remember anyone complaining about that.

> Is this the relatively old version you mean. For C++ do  you mean C++98, 
> C++03, C++11?

My first sentence was unclear, but contained the answer: C++98.  And compatible 
with more recent versions of the language. At some point I suppose we will be 
able to drop C++03 and require at least C++11, but there's no urge for this.

> All of these are relatively old.I expect that D and Java have the same 
> uncertainty.
> 
> That you use relatively old versions is meaningless because you haven't 
> specified the version. And suppose that the version baseline changes, and 
> code generated from prior versions are deprecated, or more insidious, the 
> semantics are altered. You've provided no guidance.

What are you exactly referring to here?  I am not aware of any case where the 
semantics are actually altered.

I do agree the skeletons should specific their language requirements, you are 
absolutely right.  But I dispute that changing the target language version 
(e.g. KnR to C90) ever changed some semantics.  It certainly broke builds for 
people who were still using KnR C in 2012, but it did not alter semantics in 
practice.


> This is no more than a single line in the document and/or part of --help. It 
> tells your audience what compilers they can use and what language elements 
> are available. All with a single line.

No can do.  That's something related to the skeletons.  So I will complete 
their documentation, yes.

Cheers!