On 28/07/2020 18:57, Theodore Brown wrote:
Having a closing ] makes it easier to extend Attributes with more syntax
This might be a good argument if there were actually a need to extend
attributes with more syntax. What other languages have found a need for
this? Even Rust doesn't allow additional syntax inside the brackets.
Just because they haven't, does not mean we won't. Unless there's a good
reason to do otherwise, we should provide for future flexibility where
possible.
I previously provided examples of ways in which we might want to extend
the syntax.
Most things in PHP allow some level of scope restriction, such as
private or protected. One day we may want to extend annotations to
include such a feature, such as a protected annotation that can only be
accessed by the class itself or its descendants.
#[protected MyAttribute(xyz)]
Attributes are not validated when they are encountered, this may be
something that we wish to allow attributes to opt-in to in future.
#[checked MyAttribute(xyz])
In future we might want to offer APIs that return an array of all of the
instances (moving the creation up from newInstance) and then tighten up
the behvaiour for classes which do not exist (because they might belong
to an optional package, such as debugging or code analysis). This might
come in the form of something like:
#[optional MyAttribute(xyz)]
Some of these might happen, none of these might happen, something
completely different might happen.
What is clear is we've got to support Attributes for 20, 30 years, and
we should leave the door open for easier and cleaner syntax additions if
there's no compelling reason not to.
--
Mark Randall
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