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Straw poll: Using namespaces for *any() and *all() on iterables
- Version: 0.1
- Date: 2021-01-05
- Author: Tyson Andre, tandre@php.net
- Status: Under Discussion
- First Published at: http://wiki.php.net/rfc/any_all_on_iterable_straw_poll_namespace
Introduction
The primitives *any*() and *all*() are a common part of many programming languages and help in avoiding verbosity or unnecessary abstractions.
Before adding this, I'd like to see what others think about the choice of naming pattern.
In a previous poll, the option iterable_any() was preferred over iter_any()/any(), but several responses were moderately or strongly in favor of namespaces.
- I plan to propose additional internal functions for working with iterables if this succeeds, and would want to be sure this is the best name choice going forwards.
- Additionally, this has been an opportunity for measuring overall interest in adopting namespaces for brand new categories of functionality - existing methods work on Traversables (
iterator_*) or arrays (array_*), but generally not both.
https://externals.io/message/112558
From Levi Morrison:
I want to re-iterate my opinion on this discussion thread: anything with a prefix is a hard-no from me. Namespaces are literally designed for this, and I will not vote “yes” to
iter_all,iterable_all, etc, no matter what the prefix is. Anything without a namespace is a no from me.I'm flexible on many other points, but not this one. It's 2020 (almost 2021); let's use namespaces for what they were designed for. This is a perfect opportunity; they work on more than just arrays so using the
array_prefix for consistency doesn't apply.
https://externals.io/message/112558#112588
Hey Tyson,
I know I'm being stubborn, but we have namespaces, but also an “old guard” that doesn't understand its own programming language 🤷♀️
The main thing I'm concerned about is that once we start extending this area (I assume that any & all are not going to be the last additions in this space) we will quickly run into function names that are either too generic or outright collide. For example, what if we want to add an iterator-based version of range()? Do we really want to be forced to pull a Python and call it xrange()? That's about as good as real_range()...
As such, I think it's important to prefix these somehow, though I don't care strongly how. Could be iter_all() or iterable_all(). We might even make it iterator_all() if we also adjust other existing iterator_* functions to accept iterables. I'd also be happy with iter\all() or iterable\all(), but that gets us back into namespacing discussions :)
Regards, Nikita
Discussion
Choice of namespace
This poll includes one of the naming options suggested by Levi Morrison and uses the suggested namespace for alternative options.
I could start a second straw poll and wait for those results if you had a proposal for (a namespace) in mind.Simply `Spl\all_values`. I don't think there's a need for another namespace component:
1) The SPL can disambiguate within itself.
2) It _shouldn't_ become the dumping ground of PHP.
Spl was chosen as a namespace because:
- Existing iterator/iterable functionality such as
iterator_*and data structures were placed in thesplextension, and any/all would be as well. - Existing classes are named SplObjectStorage, SplFixedArray, etc. (e.g. for
ReflectionClass->getName()) - using theSplcasing would be consistent within the |spl module. - It is less prone to conflicts than
iter- e.g. https://github.com/nikic/iter. - The
Spl\namespace can be reused for new classes/functions if they belong in thesplmodule. (I have no plans to move existing functions/classes to that namespace)
Future extension
It is possibly that functionality to check if any/all keys satisfy a predicate, or any/all combinations of entries add a predicate. If this gets added, there are two possibilities
- Add
*any_keyfor keys, and*any_entry/*any_key_value()for key+value combination - Add flags to the
*any()method, likearray_filter()
There's precedent for both choices of naming patterns, and I'm fine with either choice. Precedents include array_values() and array_keys(), as well as array_diff() and array_diff_keys()
Inconveniences of iterable\ in namespace
From https://externals.io/message/112558#112832
I've also realized that use prefix\iterable would be mildly inconvenient for users of PHP and for tooling (refactoring tools, IDEs, etc) for PHP, but still include it as an option because it's manageable and the non-namespaced prefix iterable_ was preferred in the previous poll.
php > namespace W { echo iterable::class; } W\iterable php > namespace X { use iterable; } Fatal error: Cannot use iterable as iterable because 'iterable' is a special class name in php shell code on line 1 php > namespace X { use iterable\any; /* using individual functions works */ } php > namespace Y { use PHP\iterable; function foo(iterable $x) {}} Fatal error: Cannot use PHP\iterable as iterable because 'iterable' is a special class name in php shell code on line 1 php > namespace Z { use PHP\iterable as iter; } php > namespace iterable { echo "can be polyfilled\n"; } can be polyfilled
Vote
This vote will influence the name choice for the RFC https://wiki.php.net/rfc/any_all_on_iterable
This is a ranked-choice poll (following STV) between the naming alternatives.
With STV you SHOULD rank all the choices in order (but are not required to). Don't pick the same option more than once, as that invalidates your vote.
What the functions do
See https://wiki.php.net/rfc/any_all_on_iterable
/** Determines whether any element of the iterable satisfies the predicate. */ function(iterable $input, ?callable $callback = null) { foreach ($input as $v) { if ($callback !== null ? $callback($v) : $v) { return true; } } return false; }; /** Determines whether all elements of the iterable satisfy the predicate */ function(iterable $input, ?callable $callback = null) { foreach ($input as $v) { if (!($callback !== null ? $callback($v) : $v)) { return false; } } return true; };
Rejected Choices
Using static methods instead of global functions was not considered since it would be impractical to polyfill new functions that get added in future php versions in a standard way. (e.g. IterUtils::all())
all() and iter_all()
Those were rejected in https://wiki.php.net/rfc/any_all_on_iterable_straw_poll#vote
Existing iterator methods
The prefix iterator_ was not considered. In PHP, Iterator and IteratorAggregate already exist, and classes that implement Traversable must implement either Iterator or IteratorAggregate. The name iterator_ would be misleading for functions that also accept arrays.
- I don't want to be in a situation where there are a large number of
iterator_*()functions, where some acceptTraversableand some acceptiterable. - I also don't want to be in a situation where some have $iterator as a named argument (since PHP 8.0, e.g.
iterator_to_array()) and others have $iterable. - If I was choosing names from scratch,
*foo(iterable $iterable, ...)would make more sense thaniterator_foo(iterable $iterator, ...)
Changing other iterator functions such as iterator_apply(), iterator_count(), and iterator_to_array() to accept iterator instead of Traversable(Iterator and IteratorAggregate) is out of the scope of the RFC or straw poll.
- My preference would be to add new
iterable_apply(),iterable_count(), anditerable_to_array()functions instead of modifying the existing methods. This would be possible to polyfill, and it would be less likely that code developed for 8.1+ would pass arrays that would be rejected by php 8.0 and older. - Any alternative RFCs to change the behaviors of
iterator_apply(),iterator_count(), anditerator_to_array()can be done independently of adding*any()and*all().
References
- https://externals.io/message/112558 “Straw poll: Naming for `*any()` and `*all()` on iterables”