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Re: Announcing Perl 7

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Christian Walde
July 3, 2020 17:17
Re: Announcing Perl 7
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On Fri, 03 Jul 2020 18:53:05 +0200, Paul "LeoNerd" Evans <> wrote:

> On Sat, 27 Jun 2020 01:20:06 -0700
> Darren Duncan <> wrote:
>> My central proposal is that we should be happy with a small amount of
>> well thought out file boilerplate, and that a goal of having
>> absolutely zero boilerplate is a worse option.
>> I feel that, for precedents and examples, we should not be looking to
>> what is typical with programming languages, but rather to what is
>> typical for data file or interchange or message formats or
>> communication protocols or the like.
>> We should be conceiving a Perl program as a message and that message
>> should have explicit metadata describing itself so that it can be
>> understood in the most unambiguous manner possible.  This would be
>> the boilerplate.
> Yes - some excellent thoughts there. I entirely agree. More things
> should be upfront and explicit about versioning. Even our good old
> friend HTTP starts off with
>   GET / HTTP/1.1
> So I don't think it's a bad model to consider.
>> I propose that we retain and utilize the classic "use N;" (where N is
>> a number) as the simplest form of this metadata, and make that
>> declaration mandatory at the outermost scope of each file, which is
>> to say it appears above all entity declarations in the file.
> Cautiously agree. Obviously this is going to require a fair amount of
> deprecation time before it becomes mandatory, but I could foresee a
> world in which every .pm file starts off with "use N" for some N, and
> that would be no bad thing.
>> Explicit versioning in the Perl code provides greater stability and
>> forwards/backwards compatibility than having no version declaration.
>> Anyone looking at it always knows what they're dealing with, what the
>> author's intent was.
> +1
>> There is no reason that Baby Perl can't include the 1-liner "use N",
>> that gets people used to explicit versioning right from the start.
>> We just need to explain to users that the number has an actual
>> meaning and higher numbers generally mean more features, and that it
>> isn't just some opaque constant that you set once and never change.
>> Later on, they can increase the numbers at the same time they
>> discover the existence of new features that require it; any news or
>> teachable moment that informs on the existence of a new feature also
>> says what dialect/Perl version is needed at a minimum to obtain it.
>> So making "use 5" mandatory is no worse than requiring "use
>> compat::perl5" but its more terse and more future-proof and also a
>> lot of code would already conform.
> ...
>> Now the existing tools and plans to help with migration of Perl code
>> to the version 7 dialect or tools to help deal with CPAN modules can
>> all still happen as proposed.
>> But the idea of zero boilerplate should be abandoned, and the simple
>> "use N" boilerplate be made mandatory instead.
> So much more +1.
> I overall agree with everything you've said. I've trimmed the above
> reply to only the most relevant parts, but a lot of good stuff there.
> I'm sorry I missed it first time around but I discovered it on
> re-reading the list a second time.

I wholeheartedly agree with all of this.

With regards,
Christian Walde

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