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| rfc:cachediterable [2021/06/16 23:08] – tandre | rfc:cachediterable [2021/06/17 02:37] – tandre |
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| Currently, PHP does not provide a built-in way to store the state of an arbitrary iterable for reuse later (when the iterable has arbitrary keys, or when keys might be repeated). It would be useful to do so for many use cases, such as: | Currently, PHP does not provide a built-in way to store the state of an arbitrary iterable for reuse later (when the iterable has arbitrary keys, or when keys might be repeated). It would be useful to do so for many use cases, such as: |
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| - Creating a rewindable copy of a non-rewindable Traversable (e.g. a ''Generator'') before passing that copy to a function that consumes an iterable/Traversable. (''new CachedIterator(my_generator())'') | - Creating a rewindable copy of a non-rewindable Traversable (e.g. a ''Generator'') before passing that copy to a function that consumes an iterable/Traversable. (''new ImmutableIterable(my_generator())'') |
| - Generating an ''IteratorAggregate'' from a class still implementing ''Iterator'' (e.g. ''SplObjectStorage'') so that code can independently iterate over the key-value sequences. \\ (e.g. ''foreach ($immutableKeyValueSequence as $k1 => $v1) { foreach ($immutableKeyValueSequence as $k2 => $v2) { /* process pairs */ } }'') | - Generating an ''IteratorAggregate'' from a class still implementing ''Iterator'' (e.g. ''SplObjectStorage'') so that code can independently iterate over the key-value sequences. \\ (e.g. ''foreach ($immutableKeyValueSequence as $k1 => $v1) { foreach ($immutableKeyValueSequence as $k2 => $v2) { /* process pairs */ } }'') |
| - Providing internal or userland helpers such as ''iterable_flip(iterable $input)'', ''iterable_take(iterable $input, int $limit)'', ''iterable_chunk(iterable $input, int $chunk_size)'' that act on iterables with arbitrary key/value sequences and have return values including iterables with arbitrary key/value sequences | - Providing internal or userland helpers such as ''iterable_flip(iterable $input)'', ''iterable_take(iterable $input, int $limit)'', ''iterable_chunk(iterable $input, int $chunk_size)'' that act on iterables with arbitrary key/value sequences and have return values including iterables with arbitrary key/value sequences |