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refactor: Leverage tacit programming (point free style)
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Point free style operation to avoid repeating closures that are already
existing in Compose operation.
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@drupol
drupol committed Sep 24, 2020
1 parent 675af9a commit 13b5d6d
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Showing 9 changed files with 120 additions and 124 deletions.
26 changes: 12 additions & 14 deletions src/Operation/Flatten.php
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Original file line number Diff line number Diff line change
Expand Up @@ -36,23 +36,21 @@ static function (Iterator $iterator) use ($depth): Generator {
foreach ($iterator as $key => $value) {
if (false === is_iterable($value)) {
yield $key => $value;
} elseif (1 === $depth) {
/** @psalm-var TKey $subKey */
/** @psalm-var T $subValue */
foreach ($value as $subKey => $subValue) {
yield $subKey => $subValue;
}
} else {

continue;
}

if (1 !== $depth) {
/** @psalm-var callable(Iterator<TKey, T>): Generator<TKey, T> $flatten */
$flatten = Flatten::of()($depth - 1);

/**
* @psalm-var TKey $subKey
* @psalm-var T $subValue
*/
foreach ($flatten(new IterableIterator($value)) as $subKey => $subValue) {
yield $subKey => $subValue;
}
$value = $flatten(new IterableIterator($value));
}

/** @psalm-var TKey $subKey */
/** @psalm-var T $subValue */
foreach ($value as $subKey => $subValue) {
yield $subKey => $subValue;
}
}
};
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55 changes: 29 additions & 26 deletions src/Operation/Frequency.php
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Original file line number Diff line number Diff line change
Expand Up @@ -20,42 +20,45 @@ final class Frequency extends AbstractOperation
*/
public function __invoke(): Closure
{
return
$reduceCallback =
/**
* @psalm-param Iterator<TKey, T> $iterator
* @psalm-param array<int, array{0: int, 1: T}> $storage
* @psalm-param T $value
*
* @psalm-return Generator<int, T>
* @psalm-return array<int, array{0: int, 1: T}>
*
* @param mixed $value
*/
static function (Iterator $iterator): Generator {
$storage = [];

foreach ($iterator as $value) {
$added = false;

foreach ($storage as $key => $data) {
if ($data['value'] !== $value) {
continue;
}

++$storage[$key]['count'];
$added = true;

break;
}
static function (array $storage, $value): array {
$added = false;

if (false !== $added) {
foreach ($storage as $key => $data) {
if ($data[1] !== $value) {
continue;
}

$storage[] = [
'value' => $value,
'count' => 1,
];
++$storage[$key][0];
$added = true;

break;
}

foreach ($storage as $value) {
yield $value['count'] => $value['value'];
if (false !== $added) {
return $storage;
}

$storage[] = [1, $value];

return $storage;
};

/** @psalm-var Closure(Iterator<TKey, T>): Generator<int, T> $compose */
$compose = Compose::of()(
FoldLeft::of()($reduceCallback)([]),
Flatten::of()(1),
Unpack::of()
);

return $compose;
}
}
14 changes: 5 additions & 9 deletions src/Operation/Head.php
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Original file line number Diff line number Diff line change
Expand Up @@ -20,14 +20,10 @@ final class Head extends AbstractOperation
*/
public function __invoke(): Closure
{
return
/**
* @psalm-param Iterator<TKey, T> $iterator
*
* @psalm-return Generator<TKey, T>
*/
static function (Iterator $iterator): Generator {
return yield $iterator->key() => $iterator->current();
};
/** @psalm-var Closure(Iterator<TKey, T>): Generator<TKey, T> $first */
$first = First::of();

// Point free style.
return $first;
}
}
1 change: 1 addition & 0 deletions src/Operation/Intersect.php
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ static function ($value, $key, Iterator $iterator) use ($values): bool {
/** @psalm-var Closure(Iterator<TKey, T>): Generator<TKey, T> $filter */
$filter = Filter::of()($filterCallbackFactory($values));

// Point free style.
return $filter;
};
}
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20 changes: 8 additions & 12 deletions src/Operation/Pack.php
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Original file line number Diff line number Diff line change
Expand Up @@ -16,31 +16,27 @@
final class Pack extends AbstractOperation
{
/**
* @psalm-return Closure(Iterator<TKey, T>): Generator<int, array{0:TKey, 1:T}>
* @psalm-return Closure(Iterator<TKey, T>): Generator<int, array{0: TKey, 1: T}>
*/
public function __invoke(): Closure
{
$callbackForKeys = static function (): void {
};
$callbackForValues =
$mapCallback =
/**
* @psalm-param T $initial
* @psalm-param TKey $key
* @psalm-param T $value
* @psalm-param TKey $key
*
* @psalm-return array{0: TKey, 1: T}
*
* @param mixed $initial
* @param mixed $key
* @param mixed $value
* @param mixed $key
*
* @psalm-return array{0: TKey, 1: T}
*/
static function ($initial, $key, $value): array {
static function ($value, $key): array {
return [$key, $value];
};

/** @psalm-var Closure(Iterator<TKey, T>): Generator<int, array{0: TKey, 1: T}> $compose */
$compose = Compose::of()(
Associate::of()($callbackForKeys)($callbackForValues),
Map::of()($mapCallback),
Normalize::of()
);

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72 changes: 37 additions & 35 deletions src/Operation/Since.php
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@
* @psalm-template TKey
* @psalm-template TKey of array-key
* @psalm-template T
*
* phpcs:disable Generic.WhiteSpace.ScopeIndent.IncorrectExact
*/
final class Since extends AbstractOperation
{
Expand All @@ -28,45 +30,45 @@ public function __invoke(): Closure
*/
static function (callable ...$callbacks): Closure {
return
/**
* @psalm-param Iterator<TKey, T> $iterator
*
* @psalm-return Generator<TKey, T>
*/
static function (Iterator $iterator) use ($callbacks): Generator {
$reducer =
/**
* @psalm-param Iterator<TKey, T> $iterator
*
* @psalm-return Closure(bool, callable(T, TKey): bool): bool
*/
static function (Iterator $iterator): Closure {
return
/**
* @psalm-param bool $carry
* @psalm-param callable(T, TKey): bool $callback
*/
static function (bool $carry, callable $callback) use ($iterator): bool {
return ($callback($iterator->current(), $iterator->key())) ?
$carry :
false;
};
};
/**
* @psalm-param Iterator<TKey, T> $iterator
*
* @psalm-return Generator<TKey, T>
*/
static function (Iterator $iterator) use ($callbacks): Generator {
$reducer =
/**
* @psalm-param Iterator<TKey, T> $iterator
*
* @psalm-return Closure(bool, callable(T, TKey): bool): bool
*/
static function (Iterator $iterator): Closure {
return
/**
* @psalm-param bool $carry
* @psalm-param callable(T, TKey): bool $callback
*/
static function (bool $carry, callable $callback) use ($iterator): bool {
return ($callback($iterator->current(), $iterator->key())) ?
$carry :
false;
};
};

while ($iterator->valid()) {
$result = array_reduce($callbacks, $reducer($iterator), true);
while ($iterator->valid()) {
$result = array_reduce($callbacks, $reducer($iterator), true);

if (false !== $result) {
break;
}
if (false !== $result) {
break;
}

$iterator->next();
}
$iterator->next();
}

for (; $iterator->valid(); $iterator->next()) {
yield $iterator->key() => $iterator->current();
}
};
for (; $iterator->valid(); $iterator->next()) {
yield $iterator->key() => $iterator->current();
}
};
};
}
}
8 changes: 3 additions & 5 deletions src/Operation/Unwrap.php
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Original file line number Diff line number Diff line change
Expand Up @@ -20,12 +20,10 @@ final class Unwrap extends AbstractOperation
*/
public function __invoke(): Closure
{
/** @psalm-var Closure(Iterator<TKey, array<TKey, T>>): Generator<TKey, T> $compose */
$compose = Compose::of()(
Flatten::of()(1)
);
/** @psalm-var Closure(Iterator<TKey, array<TKey, T>>): Generator<TKey, T> $flatten */
$flatten = Flatten::of()(1);

// Point free style.
return $compose;
return $flatten;
}
}
30 changes: 18 additions & 12 deletions src/Operation/Unzip.php
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@
* @psalm-template TKey
* @psalm-template TKey of array-key
* @psalm-template T
*
* phpcs:disable Generic.WhiteSpace.ScopeIndent.IncorrectExact
*/
final class Unzip extends AbstractOperation
{
Expand All @@ -20,25 +22,29 @@ final class Unzip extends AbstractOperation
*/
public function __invoke(): Closure
{
return
$reduceCallback =
/**
* @psalm-param Iterator<TKey, list<T>> $iterator
* @psalm-param array<int, list<T>> $carry
* @psalm-param iterable<TKey, T> $value
*
* @psalm-return Generator<int, list<T>>
* @psalm-return array<int, list<T>>
*/
static function (Iterator $iterator): Generator {
static function (array $carry, iterable $value): array {
$index = 0;
$result = [];

foreach ($iterator as $current) {
foreach ($current as $c) {
$result[$index++][] = $c;
}

$index = 0;
foreach ($value as $v) {
$carry[$index++][] = $v;
}

return yield from $result;
return $carry;
};

/** @psalm-var Closure(Iterator<TKey, list<T>>): Generator<int, list<T>> $compose */
$compose = Compose::of()(
FoldLeft::of()($reduceCallback)([]),
Unwrap::of()
);

return $compose;
}
}
18 changes: 7 additions & 11 deletions src/Operation/Wrap.php
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Original file line number Diff line number Diff line change
Expand Up @@ -20,27 +20,23 @@ final class Wrap extends AbstractOperation
*/
public function __invoke(): Closure
{
$callbackForKeys = static function (): void {
};
$callbackForValues =
$mapCallback =
/**
* @psalm-param T $initial
* @psalm-param TKey $key
* @psalm-param T $value
* @psalm-param TKey $key
*
* @psalm-return array<TKey, T>
*
* @param mixed $initial
* @param mixed $key
* @param mixed $value
* @param mixed $key
*
* @psalm-return array<TKey, T>
*/
static function ($initial, $key, $value): array {
static function ($value, $key): array {
return [$key => $value];
};

/** @psalm-var Closure(Iterator<TKey, T>): Generator<int, array<TKey, T>> $compose */
$compose = Compose::of()(
Associate::of()($callbackForKeys)($callbackForValues),
Map::of()($mapCallback),
Normalize::of()
);

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