Re: [RFC] Shorter attribute syntax

From: Date: Sun, 07 Jun 2020 22:32:40 +0000
Subject: Re: [RFC] Shorter attribute syntax
References: 1 2 3 4 5  Groups: php.internals 
Request: Send a blank email to internals+get-110412@lists.php.net to get a copy of this message 
On 07/06/2020 19:37, Theodore Brown wrote:

If <<Foo( <<Bar>> )>> means something like new Foo( new Bar ), then I
can imagine it being useful for <<Foo( <<Bar, Baz>> )>> to mean
new Foo( [new Bar, new Baz] ). That would actually be more convenient than
the double-at version, where you'd have to write @@Foo( [@@Bar, @@Baz] )
or use a constructor with a ...$variadic parameter.

In that example there are the same number of characters either way, so
it's not clear the nested <<>> approach would be more convenient.
And do you think it's a good idea to have an additional syntax for
creating arrays like that? It seems like it could get confusing.



True, it doesn't make a huge amount of difference.

My thinking was that passing a list of attributes as arguments to another would be quite a common case, and would add value to the special "nested attributes" syntax, which is otherwise just a weird spelling of "new" to work around implementation problems (if indeed it does actually work around them).




Ultimately, it all comes down to judgement calls - is the
double-angle-bracket syntax "too verbose", "too ugly" when nested, etc;
and does the double-at syntax make it "better enough".

Yes, I agree that there's a judgment call to make. Out of curiosity,
given these shortcomings of the double-angle-bracket syntax, do you
think there are any objective reasons to prefer it over @@ (other
than the theoretical BC break of code like @@@really_suppress_me())?



I'm not convinced there's any objective reasons to be found either way, but for the sake of "playing devil's advocate", here are a few that could be put forward:


If grouped attributes are added, they're actually slightly less verbose than repeating a double-at prefix, once you have enough attributes in the set:

Minimum spacing and punctuation requires n+3 chars vs 3n, so a saving even with 2 attributes:
<<Foo,Bar>>class Bob{}
vs
@@Foo @@Bar class Bob{}

More realistic spacing is 2n+3 vs 3n, giving a saving only with 4 or more:
<<Foo, Bar, Baz, Quux>>class Bob{}
vs
@@Foo @@Bar @@Baz @@Quuxclass Bob{}


Bracket-based syntaxes, particularly with grouping, are more clearly separated from the main code, particularly when used inline. For instance:

$f = @@Something @@AnotherThing function(@@Special @@ReallyInt int $var) {};
vs
$f = <<Something, AnotherThing>> function(<<Special, ReallyInt>> int $var) {};


Finally, typing up those examples, it occurs to me that @@ is quite a "heavy" symbol - it has a large proportion of black (or whatever colour) pixels - and inevitably a rather "fussy" one. I find it draws the eye more than the angle-brackets do, which feels unfortunate.


Regards,

-- 
Rowan Tommins (né Collins)
[IMSoP]

Thread (41 messages)

« previous php.internals (#110412) next »