[PHP-DEV] [PATCH] array_get()
Here's a patch against HEAD that implements the array_get function previously suggested on this list. I also attached a test suite, which should go in ext/standard/tests/array/array_get.phpt. Feedback is welcome. Independently, someone else had posted the same idea as a feature request for PHP 5, and if there's interest I can backport it. 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) /* Prototype: * mixed array_get ( array $search, mixed $key, mixed $default ); * Description: * Returns the value corresponding to the given key if the key exists * in the array. $key can be any value possible for an array index. * If the key does not exist, the function returns $default, or FALSE * if $default is not specified. Also works on objects. * Similar semantics to array_key_exists. */ Here is the original proposal: === array_get, a more palatable alternative to ifsetor MOTIVATION There is an unmet need for an accessor that doesn't generate an E_NOTICE when the value is missing, as shown by ongoing discussions and repeated requests for an ifsetor operator. However, ifsetor had a special-case syntax and generally didn't fit very well with the rest of the language. http://devzone.zend.com/node/view/id/1481#Heading2 has a brief summary. See the Related Functions and Proposals section for more. Reading over those ideas (firstset(), coalesce(), :?, ifset(), and a workaround using settype()), most of the best uses boil down to retrieving values from arrays. PROPOSAL As a simpler alternative to constructs such as this common double array reference... $value = isset($_POST['command']) ? $_POST['command'] : ''; I propose an array_get function, like this... $value = array_get($_POST, 'command', ''); The third argument provides a default. This function would require no special syntax, and makes a very common construct easier to read and less error-prone to type. It's a concise way of saying that missing values can be handled gracefully. Though request processing was used as an example, the function has wide applicability across many other uses of associative arrays. GREAT, BUT WHY NOT ADD IT TO AN INCLUDE FILE, INSTEAD OF THE CORE? One of the goals is to make everyday PHP code simpler and clearer. Writers of sample code snippets should be able to rely on array_get() being available. Otherwise, they will not use it. Clearer sample code particularly benefits beginners, who would probably find array_get easier to understand, but anyone else who has to read or maintain other people's code would benefit from its wide deployment in core as well. The function is generally useful enough to be part of the language, and the implementation in C is also more efficient than a PHP version. That said, a compatibility function for older versions of PHP is given below. SEMANTICS mixed array_get(array $array, mixed $key[, mixed $default = FALSE]); If $array contains the key $key, $array[$key] is returned. Otherwise $default is returned. If $default is not specified, it defaults to FALSE. (NULL would also be possible, and would more closely match other languages such as Python with its dict.get method, but other PHP functions tend to return FALSE to indicate no value.) The semantics match array_key_exists($key, $array) ? $array[$key] : $default ... but for comparison, isset($array[$key]) ? $array[$key] : $default is subtly different. The preferred array_key_exists version has these differences: 1. If $array[$key] exists but has been set to null, that null value will be returned instead of $default. This is likely to be the least surprising thing to do. 2. If $array itself is unset, an error is generated. This is good. The intention is to gracefully handle a missing $key. But if even $array itself doesn't exist, there may be another problem, such as misspelling the array variable. isset() ignores all errors, sweeping more under the rug than we typically want. IMPLEMENTATION A core C implementation of array_get() benchmarked between two and three times as fast as the implementation in PHP. I'll attach the patch after responding to feedback. See the last section for the code of the PHP implementation. RELATED FUNCTIONS AND PROPOSALS This function is different than the array_get function proposed and rejected in http://bugs.php.net/bug.php?id=28185. That function had no default value and throws a notice when the key doesn't exist, eliminating the major purpose of this function. The ?: operator doesn't serve the same purpose, because it causes an E_NOTICE for missing values. However, ?: and array_get can be used together to provide short-circuit evaluation, overcoming the limitations of bot
Re: [PHP-DEV] [PATCH] array_get()
Let me try that again with the files attached. I'll leave out the full original proposal this time. On Sep 10, 2007, at 6:12 PM, Andrew Shearer wrote: Here's a patch against HEAD that implements the array_get function previously suggested on this list. I also attached a test suite, which should go in ext/standard/tests/array/array_get.phpt. Feedback is welcome. Independently, someone else had posted the same idea as a feature request for PHP 5, and if there's interest I can backport it. 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) /* Prototype: * mixed array_get ( array $search, mixed $key, mixed $default ); * Description: * Returns the value corresponding to the given key if the key exists * in the array. $key can be any value possible for an array index. * If the key does not exist, the function returns $default, or FALSE * if $default is not specified. Also works on objects. * Similar semantics to array_key_exists. */ Here is the original proposal: ... -- Andrew Shearer http://ashearer.com/ -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
I had forgotten that attachments aren't allowed. Here are links to the patch and test suite. This ought to work. Sorry for the multiple posts, everyone. http://ashearer.com/software/array_get/2007-09-10-php6/array_get.diff http://ashearer.com/software/array_get/2007-09-10-php6/array_get.phpt On Sep 10, 2007, at 6:27 PM, Andrew Shearer wrote: Let me try that again with the files attached. I'll leave out the full original proposal this time. On Sep 10, 2007, at 6:12 PM, Andrew Shearer wrote: Here's a patch against HEAD that implements the array_get function previously suggested on this list. I also attached a test suite, which should go in ext/standard/tests/array/array_get.phpt. Feedback is welcome. Independently, someone else had posted the same idea as a feature request for PHP 5, and if there's interest I can backport it. 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) /* Prototype: * mixed array_get ( array $search, mixed $key, mixed $default ); * Description: * Returns the value corresponding to the given key if the key exists * in the array. $key can be any value possible for an array index. * If the key does not exist, the function returns $default, or FALSE * if $default is not specified. Also works on objects. * Similar semantics to array_key_exists. */ Here is the original proposal: -- Andrew Shearer http://ashearer.com/
Re: [PHP-DEV] [PATCH] array_get()
Hi, Please also add the patch provided by John Bafford last Januari. Arnold Andrew Shearer wrote: I had forgotten that attachments aren't allowed. Here are links to the patch and test suite. This ought to work. Sorry for the multiple posts, everyone. http://ashearer.com/software/array_get/2007-09-10-php6/array_get.diff http://ashearer.com/software/array_get/2007-09-10-php6/array_get.phpt On Sep 10, 2007, at 6:27 PM, Andrew Shearer wrote: Let me try that again with the files attached. I'll leave out the full original proposal this time. On Sep 10, 2007, at 6:12 PM, Andrew Shearer wrote: Here's a patch against HEAD that implements the array_get function previously suggested on this list. I also attached a test suite, which should go in ext/standard/tests/array/array_get.phpt. Feedback is welcome. Independently, someone else had posted the same idea as a feature request for PHP 5, and if there's interest I can backport it. 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) /* Prototype: * mixed array_get ( array $search, mixed $key, mixed $default ); * Description: * Returns the value corresponding to the given key if the key exists * in the array. $key can be any value possible for an array index. * If the key does not exist, the function returns $default, or FALSE * if $default is not specified. Also works on objects. * Similar semantics to array_key_exists. */ Here is the original proposal: -- Andrew Shearer http://ashearer.com/ -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
On 11.09.2007 02:12, Andrew Shearer wrote: > Here's a patch against HEAD that implements the array_get function > previously suggested on this list. I also attached a test suite, > which should go in ext/standard/tests/array/array_get.phpt. Feedback > is welcome. > > Independently, someone else had posted the same idea as a feature > request for PHP 5, and if there's interest I can backport it. > > 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) > > /* Prototype: > * mixed array_get ( array $search, mixed $key, mixed $default ); > * Description: > * Returns the value corresponding to the given key if the key exists > * in the array. $key can be any value possible for an array index. > * If the key does not exist, the function returns $default, or FALSE > * if $default is not specified. Also works on objects. > * Similar semantics to array_key_exists. > */ Can you explain, what's the difference between your implementation and this? -- Wbr, Antony Dovgal -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
On Sep 10, 2007, at 10:31 PM, Antony Dovgal wrote:
On 11.09.2007 02:12, Andrew Shearer wrote:
Here's a patch against HEAD that implements the array_get function
previously suggested on this list. I also attached a test suite,
which should go in ext/standard/tests/array/array_get.phpt. Feedback
is welcome.
Independently, someone else had posted the same idea as a feature
request for PHP 5, and if there's interest I can backport it.
40792 Open Wish: Function array_get(&$mixed, $key,
$defaultvalue)
/* Prototype:
* mixed array_get ( array $search, mixed $key, mixed $default );
* Description:
* Returns the value corresponding to the given key if the key exists
* in the array. $key can be any value possible for an array index.
* If the key does not exist, the function returns $default, or FALSE
* if $default is not specified. Also works on objects.
* Similar semantics to array_key_exists.
*/
Can you explain, what's the difference between your implementation
and this?
The overall idea is to enable cleaner code by having this function
available everywhere, including example snippets. This kind of
expression is needed all over the place, but is often verbosely
written out each time using an error-prone repetition of the array
reference. At best a custom function library is included just to get
some kind of similar function, which doesn't promote readability or
code sharing.
There are a few specific technical differences between the function
above and array_get. From the proposal:
===
SEMANTICS
[...]
The semantics match
array_key_exists($key, $array) ? $array[$key] : $default
... but for comparison,
isset($array[$key]) ? $array[$key] : $default
is subtly different. The preferred array_key_exists version has these
differences:
1. If $array[$key] exists but has been set to null, that null
value will be returned instead of $default. This is likely to be the
least surprising thing to do.
2. If $array itself is unset, an error is generated. This is good.
The intention is to gracefully handle a missing $key. But if even
$array itself doesn't exist, there may be another problem, such as
misspelling the array variable. isset() ignores all errors, sweeping
more under the rug than we typically want.
IMPLEMENTATION
A core C implementation of array_get() benchmarked between two and
three times as fast as the implementation in PHP.
[...]
COMPATIBILITY FUNCTION FOR OLDER VERSIONS OF PHP
if (!function_exists('array_get')) {
function array_get($arr, $key, $default = false) {
if (array_key_exists($key, $arr)) {
return $arr[$key];
}
else {
return $default;
}
}
}
(This version turned in the fastest times out of several variants.
Passing $arr by reference or attempting to return the result by
reference had a huge negative impact, and using the ternary ? :
operator instead of the if/else was slightly slower.)
===
For the text of the full proposal (which I didn't include in my
followups as I slowly came to the realization that attachments were
being dropped), see:
http://marc.info/?l=php-internals&m=118946242013246&w=2
--
Andrew Shearer
http://ashearer.com/
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
Hello Andrew, you can easily implement this function run time. It is not very flexible and far away from what ifsetor was meant to be. Thus I do not think it is a good idea. See comments below. marcus Tuesday, September 11, 2007, 12:12:55 AM, you wrote: > Here's a patch against HEAD that implements the array_get function > previously suggested on this list. I also attached a test suite, > which should go in ext/standard/tests/array/array_get.phpt. Feedback > is welcome. > Independently, someone else had posted the same idea as a feature > request for PHP 5, and if there's interest I can backport it. > 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) > /* Prototype: > * mixed array_get ( array $search, mixed $key, mixed $default ); array should not be passed as reference as that would be a slowdown unless the function is supposed to create the index key which according to the specs below it doesn't. > * Description: > * Returns the value corresponding to the given key if the key exists > * in the array. $key can be any value possible for an array index. > * If the key does not exist, the function returns $default, or FALSE > * if $default is not specified. Also works on objects. > * Similar semantics to array_key_exists. > */ > Here is the original proposal: > === > array_get, a more palatable alternative to ifsetor Things this cannot do but ifsetor can. - Check whether the array exists - Mulitlevel queries - Other types of queries (e.g. object members) - In theory we could have ifsetor even return a writeable reference where a non existing key would either be created or (pretty bad imo) a reference to the default value gets returned. > MOTIVATION > There is an unmet need for an accessor that doesn't generate an > E_NOTICE when the value is missing, as shown by ongoing discussions > and repeated requests for an ifsetor operator. However, ifsetor had a > special-case syntax and generally didn't fit very well with the rest > of the language. > http://devzone.zend.com/node/view/id/1481#Heading2 has a brief > summary. See the Related Functions and Proposals section for more. > Reading over those ideas (firstset(), coalesce(), :?, ifset(), and a > workaround using settype()), most of the best uses boil down to > retrieving values from arrays. > PROPOSAL > As a simpler alternative to constructs such as this common double > array reference... > > $value = isset($_POST['command']) ? $_POST['command'] : ''; > > I propose an array_get function, like this... > > $value = array_get($_POST, 'command', ''); > > The third argument provides a default. This function would require no > special syntax, and makes a very common construct easier to read and > less error-prone to type. It's a concise way of saying that missing > values can be handled gracefully. > Though request processing was used as an example, the function has > wide applicability across many other uses of associative arrays. > > GREAT, BUT WHY NOT ADD IT TO AN INCLUDE FILE, INSTEAD OF THE CORE? > One of the goals is to make everyday PHP code simpler and clearer. > Writers of sample code snippets should be able to rely on array_get() > being available. Otherwise, they will not use it. Clearer sample code > particularly benefits beginners, who would probably find array_get > easier to understand, but anyone else who has to read or maintain > other people's code would benefit from its wide deployment in core as > well. The function is generally useful enough to be part of the > language, and the implementation in C is also more efficient than a > PHP version. > That said, a compatibility function for older versions of PHP is > given below. > SEMANTICS > mixed array_get(array $array, mixed $key[, mixed $default = FALSE]); > > If $array contains the key $key, $array[$key] is returned. Otherwise > $default is returned. > > If $default is not specified, it defaults to FALSE. (NULL would also > be possible, and would more closely match other languages such as > Python with its dict.get method, but other PHP functions tend to > return FALSE to indicate no value.) > > The semantics match > > array_key_exists($key, $array) ? $array[$key] : $default > > ... but for comparison, > > isset($array[$key]) ? $array[$key] : $default > > is subtly different. The preferred array_key_exists version has these > differences: > 1. If $array[$key] exists but has been set to null, that null > value will be returned instead of $default. This is likely to be the > least surprising thing to do. > 2. If $array itself is unset, an error is generated. This is good. > The intention is to gracefully handle a missing $key. But if even > $array itself doesn'
Re: [PHP-DEV] [PATCH] array_get()
If there's a workable proposal for ifsetor() that fixes the concerns brought up by the original and is likely to go in PHP 6, that would be great. In this case, perfect can be the enemy of good. array_get() helps with many common use cases of ifsetor() while fitting into the the standard PHP syntax and function model, potentially making its adoption much easier. See below for answers to what you mentioned. On Sep 11, 2007, at 5:27 AM, Marcus Boerger wrote: Hello Andrew, you can easily implement this function run time. It is not very flexible and far away from what ifsetor was meant to be. Thus I do not think it is a good idea. See comments below. marcus Tuesday, September 11, 2007, 12:12:55 AM, you wrote: Here's a patch against HEAD that implements the array_get function previously suggested on this list. I also attached a test suite, which should go in ext/standard/tests/array/array_get.phpt. Feedback is welcome. Independently, someone else had posted the same idea as a feature request for PHP 5, and if there's interest I can backport it. 40792 Open Wish: Function array_get(&$mixed, $key, $defaultvalue) /* Prototype: * mixed array_get ( array $search, mixed $key, mixed $default ); array should not be passed as reference as that would be a slowdown unless the function is supposed to create the index key which according to the specs below it doesn't. True, as you suggest, it is not passed by reference. (That bug title was posted independently by someone who might not have thought that particular aspect through, and it isn't important to the text.) * Description: * Returns the value corresponding to the given key if the key exists * in the array. $key can be any value possible for an array index. * If the key does not exist, the function returns $default, or FALSE * if $default is not specified. Also works on objects. * Similar semantics to array_key_exists. */ Here is the original proposal: === array_get, a more palatable alternative to ifsetor Things this cannot do but ifsetor can. - Check whether the array exists True, though there's an argument that this could even be better (less error-prone) for the typical uses I've seen in my code and elsewhere, where we're interested in whether the key exists in an array we already have. An isset-like function doesn't allow you to separate the two existence checks, allowing spelling errors in the array name to go undetected when they could easily be caught. In circumstances where you really do need to check both, you can call isset() or !empty () on the array first: $value = isset($array) ? array_get($array, 'mykey') : FALSE; - Mulitlevel queries Use nested array_get(). - Other types of queries (e.g. object members) array_get() supports object members, just like array_key_exists(). - In theory we could have ifsetor even return a writeable reference where a non existing key would either be created or (pretty bad imo) a reference to the default value gets returned. Something like that would be nice, but it doesn't exist and I haven't seen a concrete proposal for it. MOTIVATION There is an unmet need for an accessor that doesn't generate an E_NOTICE when the value is missing, as shown by ongoing discussions and repeated requests for an ifsetor operator. However, ifsetor had a special-case syntax and generally didn't fit very well with the rest of the language. http://devzone.zend.com/node/view/id/1481#Heading2 has a brief summary. See the Related Functions and Proposals section for more. Reading over those ideas (firstset(), coalesce(), :?, ifset(), and a workaround using settype()), most of the best uses boil down to retrieving values from arrays. PROPOSAL As a simpler alternative to constructs such as this common double array reference... $value = isset($_POST['command']) ? $_POST ['command'] : ''; I propose an array_get function, like this... $value = array_get($_POST, 'command', ''); The third argument provides a default. This function would require no special syntax, and makes a very common construct easier to read and less error-prone to type. It's a concise way of saying that missing values can be handled gracefully. Though request processing was used as an example, the function has wide applicability across many other uses of associative arrays. GREAT, BUT WHY NOT ADD IT TO AN INCLUDE FILE, INSTEAD OF THE CORE? One of the goals is to make everyday PHP code simpler and clearer. Writers of sample code snippets should be able to rely on array_get() being available. Otherwise, they will not use it. Clearer sample code particularly benefits beginners, who would probably find array_get easier to understand, but anyone else who has to read or maintain other people's code would benefit from its wide deployment in core as well. The function is generally useful enough to be part of the language, and
Re: [PHP-DEV] [PATCH] array_get()
Hello Andrew, did you check out '?:' shortcut in HEAD? php -r 'echo 4?:2;' -> 4 php -r 'echo 0?:2;' -> 2 best regards marcus Tuesday, September 11, 2007, 3:20:46 PM, you wrote: > If there's a workable proposal for ifsetor() that fixes the concerns > brought up by the original and is likely to go in PHP 6, that would > be great. > In this case, perfect can be the enemy of good. array_get() helps > with many common use cases of ifsetor() while fitting into the the > standard PHP syntax and function model, potentially making its > adoption much easier. > See below for answers to what you mentioned. > On Sep 11, 2007, at 5:27 AM, Marcus Boerger wrote: >> Hello Andrew, >> >> you can easily implement this function run time. It is not very >> flexible >> and far away from what ifsetor was meant to be. Thus I do not think >> it is a >> good idea. See comments below. >> >> marcus >> >> Tuesday, September 11, 2007, 12:12:55 AM, you wrote: >> >>> Here's a patch against HEAD that implements the array_get function >>> previously suggested on this list. I also attached a test suite, >>> which should go in ext/standard/tests/array/array_get.phpt. Feedback >>> is welcome. >> >>> Independently, someone else had posted the same idea as a feature >>> request for PHP 5, and if there's interest I can backport it. >> >>> 40792 Open Wish: Function array_get(&$mixed, $key, >>> $defaultvalue) >> >>> /* Prototype: >>> * mixed array_get ( array $search, mixed $key, mixed $default ); >> >> array should not be passed as reference as that would be a slowdown >> unless >> the function is supposed to create the index key which according to >> the >> specs below it doesn't. > True, as you suggest, it is not passed by reference. (That bug title > was posted independently by someone who might not have thought that > particular aspect through, and it isn't important to the text.) >> >>> * Description: >>> * Returns the value corresponding to the given key if the key exists >>> * in the array. $key can be any value possible for an array index. >>> * If the key does not exist, the function returns $default, or FALSE >>> * if $default is not specified. Also works on objects. >>> * Similar semantics to array_key_exists. >>> */ >> >>> Here is the original proposal: >>> === >>> array_get, a more palatable alternative to ifsetor >> >> Things this cannot do but ifsetor can. >> - Check whether the array exists > True, though there's an argument that this could even be better (less > error-prone) for the typical uses I've seen in my code and elsewhere, > where we're interested in whether the key exists in an array we > already have. An isset-like function doesn't allow you to separate > the two existence checks, allowing spelling errors in the array name > to go undetected when they could easily be caught. In circumstances > where you really do need to check both, you can call isset() or !empty > () on the array first: > $value = isset($array) ? array_get($array, 'mykey') : FALSE; >> - Mulitlevel queries > Use nested array_get(). >> - Other types of queries (e.g. object members) > array_get() supports object members, just like array_key_exists(). >> - In theory we could have ifsetor even return a writeable reference >> where a >> non existing key would either be created or (pretty bad imo) a >> reference to >> the default value gets returned. > Something like that would be nice, but it doesn't exist and I haven't > seen a concrete proposal for it. >> >>> MOTIVATION >> >>> There is an unmet need for an accessor that doesn't generate an >>> E_NOTICE when the value is missing, as shown by ongoing discussions >>> and repeated requests for an ifsetor operator. However, ifsetor had a >>> special-case syntax and generally didn't fit very well with the rest >>> of the language. >> >>> http://devzone.zend.com/node/view/id/1481#Heading2 has a brief >>> summary. See the Related Functions and Proposals section for more. >> >>> Reading over those ideas (firstset(), coalesce(), :?, ifset(), and a >>> workaround using settype()), most of the best uses boil down to >>> retrieving values from arrays. >> >> >>> PROPOSAL >> >>> As a simpler alternative to constructs such as this common double >>> array reference... >>> >>> $value = isset($_POST['command']) ? $_POST >>> ['command'] : ''; >>> >>> I propose an array_get function, like this... >>> >>> $value = array_get($_POST, 'command', ''); >>> >>> The third argument provides a default. This function would require no >>> special syntax, and makes a very common construct easier to read and >>> less error-prone to type. It's a concise way of saying that missing >>> values can be handled gracefully. >> >>> Though request processing was used as an example, the function has >>> wide applicability across many other uses of associative arrays. >> >>> >>> GREAT, BUT WHY NOT ADD IT TO AN INCLUDE FILE, INSTEAD OF THE
Re: [PHP-DEV] [PATCH] array_get()
On 9/11/07, Marcus Boerger <[EMAIL PROTECTED]> wrote: > Hello Andrew, > > did you check out '?:' shortcut in HEAD? > > php -r 'echo 4?:2;' -> 4 > php -r 'echo 0?:2;' -> 2 > > best regards > marcus Yes, I had hoped that the ?: operator would solve this. But it doesn't serve the same purpose, because it causes an E_NOTICE for missing values. However, ?: and array_get can be used together to provide short-circuit evaluation, overcoming the limitations of both. Example: array_get($_GET, 'foo') ?: slowDefaultCalculation() Here is a test of ?: with CVS HEAD + the array_get function: >>> var_dump($_SERVER['test'] ?: 'nope'); PHP Notice: Undefined index: test in - on line 2 string(4) "nope" >>> var_dump(array_get($_SERVER, 'test', 'nope')); string(4) "nope" > > Tuesday, September 11, 2007, 3:20:46 PM, you wrote: > > > If there's a workable proposal for ifsetor() that fixes the concerns > > brought up by the original and is likely to go in PHP 6, that would > > be great. > > > In this case, perfect can be the enemy of good. array_get() helps > > with many common use cases of ifsetor() while fitting into the the > > standard PHP syntax and function model, potentially making its > > adoption much easier. > > > See below for answers to what you mentioned. > > > On Sep 11, 2007, at 5:27 AM, Marcus Boerger wrote: > > >> Hello Andrew, > >> > >> you can easily implement this function run time. It is not very > >> flexible > >> and far away from what ifsetor was meant to be. Thus I do not think > >> it is a > >> good idea. See comments below. > >> > >> marcus > >> > >> Tuesday, September 11, 2007, 12:12:55 AM, you wrote: > >> > >>> Here's a patch against HEAD that implements the array_get function > >>> previously suggested on this list. I also attached a test suite, > >>> which should go in ext/standard/tests/array/array_get.phpt. Feedback > >>> is welcome. > >> > >>> Independently, someone else had posted the same idea as a feature > >>> request for PHP 5, and if there's interest I can backport it. > >> > >>> 40792 Open Wish: Function array_get(&$mixed, $key, > >>> $defaultvalue) > >> > >>> /* Prototype: > >>> * mixed array_get ( array $search, mixed $key, mixed $default ); > >> > >> array should not be passed as reference as that would be a slowdown > >> unless > >> the function is supposed to create the index key which according to > >> the > >> specs below it doesn't. > > > True, as you suggest, it is not passed by reference. (That bug title > > was posted independently by someone who might not have thought that > > particular aspect through, and it isn't important to the text.) > > >> > >>> * Description: > >>> * Returns the value corresponding to the given key if the key exists > >>> * in the array. $key can be any value possible for an array index. > >>> * If the key does not exist, the function returns $default, or FALSE > >>> * if $default is not specified. Also works on objects. > >>> * Similar semantics to array_key_exists. > >>> */ > >> > >>> Here is the original proposal: > >>> === > >>> array_get, a more palatable alternative to ifsetor > >> > >> Things this cannot do but ifsetor can. > >> - Check whether the array exists > > True, though there's an argument that this could even be better (less > > error-prone) for the typical uses I've seen in my code and elsewhere, > > where we're interested in whether the key exists in an array we > > already have. An isset-like function doesn't allow you to separate > > the two existence checks, allowing spelling errors in the array name > > to go undetected when they could easily be caught. In circumstances > > where you really do need to check both, you can call isset() or !empty > > () on the array first: > > $value = isset($array) ? array_get($array, 'mykey') : FALSE; > > >> - Mulitlevel queries > > Use nested array_get(). > > >> - Other types of queries (e.g. object members) > > array_get() supports object members, just like array_key_exists(). > > >> - In theory we could have ifsetor even return a writeable reference > >> where a > >> non existing key would either be created or (pretty bad imo) a > >> reference to > >> the default value gets returned. > > Something like that would be nice, but it doesn't exist and I haven't > > seen a concrete proposal for it. > > >> > >>> MOTIVATION > >> > >>> There is an unmet need for an accessor that doesn't generate an > >>> E_NOTICE when the value is missing, as shown by ongoing discussions > >>> and repeated requests for an ifsetor operator. However, ifsetor had a > >>> special-case syntax and generally didn't fit very well with the rest > >>> of the language. > >> > >>> http://devzone.zend.com/node/view/id/1481#Heading2 has a brief > >>> summary. See the Related Functions and Proposals section for more. > >> > >>> Reading over those ideas (firstset(), coalesce(), :?, ifset(), and a > >>> workaround using settype()), most of the best uses boil down to > >>> retrieving values from arrays. > >>
Re: [PHP-DEV] [PATCH] array_get()
Hello Andrew, how about @?: style? Like: $val = $myarray[$key] ?: $default; marcus Tuesday, September 11, 2007, 6:33:42 PM, you wrote: > On 9/11/07, Marcus Boerger <[EMAIL PROTECTED]> wrote: >> Hello Andrew, >> >> did you check out '?:' shortcut in HEAD? >> >> php -r 'echo 4?:2;' -> 4 >> php -r 'echo 0?:2;' -> 2 >> >> best regards >> marcus > Yes, I had hoped that the ?: operator would solve this. But it doesn't > serve the same purpose, because it causes an E_NOTICE for missing > values. However, ?: and array_get can be used together to provide > short-circuit evaluation, overcoming the limitations of both. > Example: > array_get($_GET, 'foo') ?: slowDefaultCalculation() > Here is a test of ?: with CVS HEAD + the array_get function: var_dump($_SERVER['test'] ?: 'nope'); > PHP Notice: Undefined index: test in - on line 2 > string(4) "nope" var_dump(array_get($_SERVER, 'test', 'nope')); > string(4) "nope" >> >> Tuesday, September 11, 2007, 3:20:46 PM, you wrote: >> >> > If there's a workable proposal for ifsetor() that fixes the concerns >> > brought up by the original and is likely to go in PHP 6, that would >> > be great. >> >> > In this case, perfect can be the enemy of good. array_get() helps >> > with many common use cases of ifsetor() while fitting into the the >> > standard PHP syntax and function model, potentially making its >> > adoption much easier. >> >> > See below for answers to what you mentioned. >> >> > On Sep 11, 2007, at 5:27 AM, Marcus Boerger wrote: >> >> >> Hello Andrew, >> >> >> >> you can easily implement this function run time. It is not very >> >> flexible >> >> and far away from what ifsetor was meant to be. Thus I do not think >> >> it is a >> >> good idea. See comments below. >> >> >> >> marcus >> >> >> >> Tuesday, September 11, 2007, 12:12:55 AM, you wrote: >> >> >> >>> Here's a patch against HEAD that implements the array_get function >> >>> previously suggested on this list. I also attached a test suite, >> >>> which should go in ext/standard/tests/array/array_get.phpt. Feedback >> >>> is welcome. >> >> >> >>> Independently, someone else had posted the same idea as a feature >> >>> request for PHP 5, and if there's interest I can backport it. >> >> >> >>> 40792 Open Wish: Function array_get(&$mixed, $key, >> >>> $defaultvalue) >> >> >> >>> /* Prototype: >> >>> * mixed array_get ( array $search, mixed $key, mixed $default ); >> >> >> >> array should not be passed as reference as that would be a slowdown >> >> unless >> >> the function is supposed to create the index key which according to >> >> the >> >> specs below it doesn't. >> >> > True, as you suggest, it is not passed by reference. (That bug title >> > was posted independently by someone who might not have thought that >> > particular aspect through, and it isn't important to the text.) >> >> >> >> >>> * Description: >> >>> * Returns the value corresponding to the given key if the key exists >> >>> * in the array. $key can be any value possible for an array index. >> >>> * If the key does not exist, the function returns $default, or FALSE >> >>> * if $default is not specified. Also works on objects. >> >>> * Similar semantics to array_key_exists. >> >>> */ >> >> >> >>> Here is the original proposal: >> >>> === >> >>> array_get, a more palatable alternative to ifsetor >> >> >> >> Things this cannot do but ifsetor can. >> >> - Check whether the array exists >> > True, though there's an argument that this could even be better (less >> > error-prone) for the typical uses I've seen in my code and elsewhere, >> > where we're interested in whether the key exists in an array we >> > already have. An isset-like function doesn't allow you to separate >> > the two existence checks, allowing spelling errors in the array name >> > to go undetected when they could easily be caught. In circumstances >> > where you really do need to check both, you can call isset() or !empty >> > () on the array first: >> > $value = isset($array) ? array_get($array, 'mykey') : FALSE; >> >> >> - Mulitlevel queries >> > Use nested array_get(). >> >> >> - Other types of queries (e.g. object members) >> > array_get() supports object members, just like array_key_exists(). >> >> >> - In theory we could have ifsetor even return a writeable reference >> >> where a >> >> non existing key would either be created or (pretty bad imo) a >> >> reference to >> >> the default value gets returned. >> > Something like that would be nice, but it doesn't exist and I haven't >> > seen a concrete proposal for it. >> >> >> >> >>> MOTIVATION >> >> >> >>> There is an unmet need for an accessor that doesn't generate an >> >>> E_NOTICE when the value is missing, as shown by ongoing discussions >> >>> and repeated requests for an ifsetor operator. However, ifsetor had a >> >>> special-case syntax and generally didn't fit very well with the rest >> >>> of the language. >> >> >> >>> http://devzone.zend.com/node/view/id/1481#Heading2
Re: [PHP-DEV] [PATCH] array_get()
On Tue, 2007-09-11 at 18:54 +0200, Marcus Boerger wrote: > Hello Andrew, > > how about @?: style? > > Like: $val = $myarray[$key] ?: $default; Did you mean like: @$val = $myarray[$key] ?: $default; Because that's an expensive assignment since it will hit the error handler when the index is not assigned. I thought the ifsetor system was going to throttle undefined index notices for the left operand. Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
On 9/11/07, Marcus Boerger <[EMAIL PROTECTED]> wrote: > Hello Andrew, > > how about @?: style? > > Like: $val = $myarray[$key] ?: $default; > > marcus There are drawbacks with using the @ style regularly. One is the lack of error checking: all error messages generated by finding the array itself or creating the key are suppressed, which are errors it would probably be better to see. There are also performance considerations. Changing the error reporting level internally to suppress errors and then restoring it has a cost. Testing 100,000 iterations: array_get() time taken, with default: 0.818 sec array_get() time taken, no default: 0.565 sec @ time taken, with default: 2.539 sec @ time taken, no default: 2.43 sec (All the above times were similar whether or not the element was found in the array, and whether the array was small or large.) Even a pure-PHP implementation of array_get is almost twice as efficient as using @. > Tuesday, September 11, 2007, 6:33:42 PM, you wrote: > > > On 9/11/07, Marcus Boerger <[EMAIL PROTECTED]> wrote: > >> Hello Andrew, > >> > >> did you check out '?:' shortcut in HEAD? > >> > >> php -r 'echo 4?:2;' -> 4 > >> php -r 'echo 0?:2;' -> 2 > >> > >> best regards > >> marcus > > > Yes, I had hoped that the ?: operator would solve this. But it doesn't > > serve the same purpose, because it causes an E_NOTICE for missing > > values. However, ?: and array_get can be used together to provide > > short-circuit evaluation, overcoming the limitations of both. > > > Example: > > array_get($_GET, 'foo') ?: slowDefaultCalculation() > > > > Here is a test of ?: with CVS HEAD + the array_get function: > > var_dump($_SERVER['test'] ?: 'nope'); > > PHP Notice: Undefined index: test in - on line 2 > > string(4) "nope" > > var_dump(array_get($_SERVER, 'test', 'nope')); > > string(4) "nope" > > >> > >> Tuesday, September 11, 2007, 3:20:46 PM, you wrote: > >> > >> > If there's a workable proposal for ifsetor() that fixes the concerns > >> > brought up by the original and is likely to go in PHP 6, that would > >> > be great. > >> > >> > In this case, perfect can be the enemy of good. array_get() helps > >> > with many common use cases of ifsetor() while fitting into the the > >> > standard PHP syntax and function model, potentially making its > >> > adoption much easier. > >> > >> > See below for answers to what you mentioned. > >> > >> > On Sep 11, 2007, at 5:27 AM, Marcus Boerger wrote: > >> > >> >> Hello Andrew, > >> >> > >> >> you can easily implement this function run time. It is not very > >> >> flexible > >> >> and far away from what ifsetor was meant to be. Thus I do not think > >> >> it is a > >> >> good idea. See comments below. > >> >> > >> >> marcus > >> >> > >> >> Tuesday, September 11, 2007, 12:12:55 AM, you wrote: > >> >> > >> >>> Here's a patch against HEAD that implements the array_get function > >> >>> previously suggested on this list. I also attached a test suite, > >> >>> which should go in ext/standard/tests/array/array_get.phpt. Feedback > >> >>> is welcome. > >> >> > >> >>> Independently, someone else had posted the same idea as a feature > >> >>> request for PHP 5, and if there's interest I can backport it. > >> >> > >> >>> 40792 Open Wish: Function array_get(&$mixed, $key, > >> >>> $defaultvalue) > >> >> > >> >>> /* Prototype: > >> >>> * mixed array_get ( array $search, mixed $key, mixed $default ); > >> >> > >> >> array should not be passed as reference as that would be a slowdown > >> >> unless > >> >> the function is supposed to create the index key which according to > >> >> the > >> >> specs below it doesn't. > >> > >> > True, as you suggest, it is not passed by reference. (That bug title > >> > was posted independently by someone who might not have thought that > >> > particular aspect through, and it isn't important to the text.) > >> > >> >> > >> >>> * Description: > >> >>> * Returns the value corresponding to the given key if the key exists > >> >>> * in the array. $key can be any value possible for an array index. > >> >>> * If the key does not exist, the function returns $default, or FALSE > >> >>> * if $default is not specified. Also works on objects. > >> >>> * Similar semantics to array_key_exists. > >> >>> */ > >> >> > >> >>> Here is the original proposal: > >> >>> === > >> >>> array_get, a more palatable alternative to ifsetor > >> >> > >> >> Things this cannot do but ifsetor can. > >> >> - Check whether the array exists > >> > True, though there's an argument that this could even be better (less > >> > error-prone) for the typical uses I've seen in my code and elsewhere, > >> > where we're interested in whether the key exists in an array we > >> > already have. An isset-like function doesn't allow you to separate > >> > the two existence checks, allowing spelling errors in the array name > >> > to go undetected when they could easily be caught. In circumstances > >> > where you really do need to check both, you ca
Re: [PHP-DEV] [PATCH] array_get()
Hello Robert, yeah ifsetor if much better than the @-?: combination. But for 5.3 that would be all we could do. For 6 and in the long run we might do a real ifsetor. If ever we could come to a consensus... and no i don't really like to restart discussions on ifsetor at this point. marcus Tuesday, September 11, 2007, 7:17:02 PM, you wrote: > On Tue, 2007-09-11 at 18:54 +0200, Marcus Boerger wrote: >> Hello Andrew, >> >> how about @?: style? >> >> Like: $val = $myarray[$key] ?: $default; > Did you mean like: > @$val = $myarray[$key] ?: $default; > Because that's an expensive assignment since it will hit the error > handler when the index is not assigned. I thought the ifsetor system was > going to throttle undefined index notices for the left operand. > Cheers, > Rob. > -- > ... > SwarmBuy.com - http://www.swarmbuy.com > Leveraging the buying power of the masses! > ... Best regards, Marcus -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
On 9/12/07, Marcus Boerger <[EMAIL PROTECTED]> wrote:
>
> Hello Robert,
>
> yeah ifsetor if much better than the @-?: combination. But for 5.3 that
> would be all we could do. For 6 and in the long run we might do a real
> ifsetor. If ever we could come to a consensus... and no i don't really
> like
> to restart discussions on ifsetor at this point.
It was my understanding that ifsetor had been rejected long ago, after going
around the list a few times after your proposal of it in 2004. I'd hate to
hold up other language progress in the hopes of eventually restarting
discussion on it, unless you'd like to bring a modified proposal now.
Meanwhile, array_get() provides the most-needed functionality while avoiding
the issues that prevented ifsetor's acceptance.
There's a backward compatibility problem with ifsetor: its special syntax
means that there's no way to write a pure-PHP userland version of it. The
effect is that there's no upgrade path for applications that have to
straddle both old and new versions of PHP, and practical usefulness of
ifsetor would be delayed for years after release.
Of course, accepting array_get() now would not preclude bringing up ifsetor
again someday on its unique merits.
Here is the patch and unit test file for array_get():
http://ashearer.com/software/array_get/2007-09-10-php6/array_get.diffhttp://ashearer.com/software/array_get/2007-09-10-php6/array_get.phpt
And here is the backward compatibility function:
if (!function_exists('array_get')) {
function array_get($arr, $key, $default = false) {
if (array_key_exists($key, $arr)) {
return $arr[$key];
}
else {
return $default;
}
}
}
Tuesday, September 11, 2007, 7:17:02 PM, you wrote:
>
> > On Tue, 2007-09-11 at 18:54 +0200, Marcus Boerger wrote:
> >> Hello Andrew,
> >>
> >> how about @?: style?
> >>
> >> Like: $val = $myarray[$key] ?: $default;
>
> > Did you mean like:
>
> > @$val = $myarray[$key] ?: $default;
>
> > Because that's an expensive assignment since it will hit the error
> > handler when the index is not assigned. I thought the ifsetor system was
> > going to throttle undefined index notices for the left operand.
>
> > Cheers,
> > Rob.
> Best regards,
> Marcus
>
>
Re: [PHP-DEV] [PATCH] array_get()
On Wed, 2007-09-12 at 13:53 -0400, Andrew Shearer wrote:
>
>
> Here is the patch and unit test file for array_get():
>
> http://ashearer.com/software/array_get/2007-09-10-php6/array_get.diff
> http://ashearer.com/software/array_get/2007-09-10-php6/array_get.phpt
>
>
> And here is the backward compatibility function:
>
> if (!function_exists('array_get')) {
> function array_get($arr, $key, $default = false) {
> if (array_key_exists($key, $arr)) {
> return $arr[$key];
> }
> else {
> return $default;
> }
> }
> }
IMHO the default value for $default should be null. That way it has the
same return value as using an undefined index on an array.
Comments?
Cheers,
Rob.
--
...
SwarmBuy.com - http://www.swarmbuy.com
Leveraging the buying power of the masses!
...
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
Andrew Shearer wrote: Meanwhile, array_get() provides the most-needed functionality while avoiding the issues that prevented ifsetor's acceptance. Aside from lack of BC hacks what is the issue? I remember some fussing about the name, but I find this a joke of an argument. You cant get much clearer a name than ifsetor(). There's a backward compatibility problem with ifsetor: its special syntax means that there's no way to write a pure-PHP userland version of it. The effect is that there's no upgrade path for applications that have to straddle both old and new versions of PHP, and practical usefulness of ifsetor would be delayed for years after release. I use ifsetor() type functionality on a daily basis. As such I would appreciate it if it would be an operator and would make its way not only into php 6, but also php 5.3. Marcus's half solution is not a solution to what I need. Andrew's solution gets close enough to solve my real world needs. Now if I could just see the slightest bit if a real argument against ifsetor(), I might even vote for array_get() (not sure if I appreciate the name though). regards, Lukas -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
On Sep 12, 2007, at 2:25 PM, Lukas Kahwe Smith wrote: Andrew Shearer wrote: Meanwhile, array_get() provides the most-needed functionality while avoiding the issues that prevented ifsetor's acceptance. Aside from lack of BC hacks what is the issue? I remember some fussing about the name, but I find this a joke of an argument. You cant get much clearer a name than ifsetor(). There's a backward compatibility problem with ifsetor: its special syntax means that there's no way to write a pure-PHP userland version of it. The effect is that there's no upgrade path for applications that have to straddle both old and new versions of PHP, and practical usefulness of ifsetor would be delayed for years after release. I use ifsetor() type functionality on a daily basis. As such I would appreciate it if it would be an operator and would make its way not only into php 6, but also php 5.3. Marcus's half solution is not a solution to what I need. Andrew's solution gets close enough to solve my real world needs. Now if I could just see the slightest bit if a real argument against ifsetor (), I might even vote for array_get() (not sure if I appreciate the name though). regards, Lukas I think we want the same thing. We both want the essential functionality in PHP one way or another. If ifsetor was in the running now, I'd support it. But after seeing the discussion and lack of consensus on it since 2004, I'm sure that the best way to reach the goal is to champion array_get(). Other suggestions for the name are welcome, but the choice of it was careful. array_get() has at least one precendent, the Python dict.get () method, which works basically the same way. The fact that the same name and function signature (give or take a reference) was also suggested completely independently in a PHP wishlist item means it's probably on the right track. -- Andrew Shearer http://ashearer.com/ -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
Hi, On Wed, 12 Sep 2007 20:25:39 +0200, in php.internals [EMAIL PROTECTED] (Lukas Kahwe Smith) wrote: >Aside from lack of BC hacks what is the issue? I remember some fussing >about the name, but I find this a joke of an argument. You cant get much >clearer a name than ifsetor(). just my opinion on the color of the bike shed: Maybe a function named like coalesce() as known from SQL. Although an unset variable yields NULL, this is not the same as testing whether the variable is actually set or not. But still, if it would return the first non-null value then it might be good in conjunction with user input. I'm not too fond of a function that begins with if* - it might misdirect people to think it's a control structure. (and now back to your original programme) -- - Peter Brodersen -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
On 9/13/07, Peter Brodersen <[EMAIL PROTECTED]> wrote: > I'm not too fond of a function that begins with if* - it might > misdirect people to think it's a control structure. ifsetor was not a function (like isset). --Pierre -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] [PATCH] array_get()
Hello Andrew,
if we go the array_get() route as a short half solution to hopefully make
a lot of people happy (at least it would serve $_GET/_REQUEST etc needs).
Then I think we should make it a bit more useable:
Get the default or the multilevel subscription of $ar
proto mixed array_get(array $ar, mixed index*, mixed $default)
function array_get(array $ar) {
$ret = $ar;
for ($i=1; $i < func_num_args() - 1; ++$i) {
$idx = func_get_arg($i);
if (array_key_exists($idx, $ret)) {
$ret = $ret[$idx];
} else {
if (func_num_args() > 1) {
return func_get_arg(func_num_args() - 1);
} else {
return NULL;
}
}
}
return $ret;
}
best regards
marcus
Thursday, September 13, 2007, 2:54:51 PM, you wrote:
> On Sep 12, 2007, at 2:25 PM, Lukas Kahwe Smith wrote:
>> Andrew Shearer wrote:
>>
>>> Meanwhile, array_get() provides the most-needed functionality
>>> while avoiding
>>> the issues that prevented ifsetor's acceptance.
>>
>> Aside from lack of BC hacks what is the issue? I remember some
>> fussing about the name, but I find this a joke of an argument. You
>> cant get much clearer a name than ifsetor().
>>
>>> There's a backward compatibility problem with ifsetor: its special
>>> syntax
>>> means that there's no way to write a pure-PHP userland version of
>>> it. The
>>> effect is that there's no upgrade path for applications that have to
>>> straddle both old and new versions of PHP, and practical
>>> usefulness of
>>> ifsetor would be delayed for years after release.
>>
>>
>> I use ifsetor() type functionality on a daily basis. As such I
>> would appreciate it if it would be an operator and would make its
>> way not only into php 6, but also php 5.3.
>>
>> Marcus's half solution is not a solution to what I need. Andrew's
>> solution gets close enough to solve my real world needs. Now if I
>> could just see the slightest bit if a real argument against ifsetor
>> (), I might even vote for array_get() (not sure if I appreciate the
>> name though).
>>
>> regards,
>> Lukas
> I think we want the same thing. We both want the essential
> functionality in PHP one way or another. If ifsetor was in the
> running now, I'd support it. But after seeing the discussion and lack
> of consensus on it since 2004, I'm sure that the best way to reach
> the goal is to champion array_get().
> Other suggestions for the name are welcome, but the choice of it was
> careful. array_get() has at least one precendent, the Python dict.get
> () method, which works basically the same way. The fact that the same
> name and function signature (give or take a reference) was also
> suggested completely independently in a PHP wishlist item means it's
> probably on the right track.
> --
> Andrew Shearer
> http://ashearer.com/
Best regards,
Marcus
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