9 ms·

The introduction of list comprehensions is nice and should replace numerous functions. For example, I'm not sure why they're adding the array_column function in

by Smerity 14y ago

The introduction of list comprehensions is nice and should replace numerous functions. For example, I'm not sure why they're adding the array_column function into PHP 5.5 at the same time as list comprehensions as: $names = array_column($users, 'name'); // is the same as $names = [foreach ($users as $user) yield $user['name']]; The only possible reason would be due to a significant speed difference, but I'd suggest improving the efficiency of the list comprehension system (even if just for common cases) than adding more functions. As opposed to the introduction of list comprehensions, I can't say I like the solution for parameter skipping though... I disagree with the author -- many optional arguments is not a problem, but only if keyword arguments or a similar style are used. Consider the example they give: // This create query function in PHP create_query("deleted=0", "name", default, default, false); // could be represented like this with keyword arguments create_query("deleted=0", "name", escape_arguments=false) I tend to find keyword arguments serve the purpose of self documentation as well -- I still have no clue what the false flag would be for the PHP create_query statement. Keyword arguments and many optional arguments can allow for beautiful and flexible functions, such as the Python Requests library[1]. r = requests.get('https://api.github.com/xyz') # or we could add a few more complications # -- no "defaults" in sight and also self documenting r = requests.get('https://api.github.com/xyz', auth=('user', 'pass'), timeout=0.5, allow_redirects=True) [1]: http://docs.python-requests.org/ http://docs.python-requests.org/

conradfr 14y ago
I, for one, never understood why there was no "default" keyword available, but the python example is great as well. About the rest of the article : - the modified empty() is nice, while I still think this function accepts to much thing as empty, or at least should be more flexible. Getter/setter : finally. Now I don't get why there is no readonly keyword which would put the variable as readonly only for the class' outer world.
- shakesbeard 14y ago
  The article clearly states that there are more features like a read-only keyword. https://wiki.php.net/rfc/propertygetsetsyntax-as-implemented https://wiki.php.net/rfc/propertygetsetsyntax-as-implemented
  - jasonlotito 14y ago
    That's not what he's referring to. He's specifically referring to a read-only that only affects external classes. So, the object itself could write to that field, but nothing else could.
    - shakesbeard 14y ago
      You can set the visibility of both the properties and the getters/setters. class Foo { private $fuzz; protected $Bar { get { return $this->fuzz; } private set { $this->fuzz = $value; } } }
      - jasonlotito 14y ago
        Yes. I understand that. My point was just that he specifically wanted a read-only.
RobAley 14y ago
I agree with you on using keyword arguments, it makes it more obvious (and where there are many optional parameters, may save some typing!). With regards to the array_column function, PHP has a history of providing such functions for common operations, even where the same functionality can be replicated with more generic code constructs. For me, the function example you provide is more readable than the comprehension example, requires less typing and provides less room for mistakes. I.E. its simpler in this case, and that’s part of the way PHP rolls. There is of course an argument that functions like this should be provided by external libraries or frameworks rather than in the core of the language, but that debate has been had many times and PHP has come down on the side of including them. This is one of the reasons developers like me like PHP. YMMV.
frosas 14y ago
I agree keyword arguments are a better solution (but probably harder to implement). Right now this is how I do this: function salute($user, array $options = null) { $options = (array) $options + array('shout' => false); $salutation = "Hi $user!"; if ($options['shout']) $salutation = strtoupper($salutation); return $salutation; }
- smsm42 14y ago
  It is significantly harder to implement, especially if you think about what happens with existing functions, especially internal ones.
geon 14y ago
> I'm not sure why they're adding the array_column function Isn't the function call much more readable than the comprehension? At least as a beginner, I found the large set of built in functions to be one of the strongest points of PHP.
- Smerity 14y ago
  One major disadvantage with so many functions is the cluttered global namespace[1]. PHP only added namespaces in 5.3.0 and can't modularize their globals into namespaces without causing massive backwards compatibility problems. PHP is stuck with a polluted global namespace, I'd be wary of adding more. Mind you, I'm well aware that this feeling could just be as I'm primarily a Python coder -- in PHP, you perform array_keys($xyz) whilst in Python it's xyz.keys(). Whilst you might consider Python as cheating by pushing all the functions onto the objects, it results in a far happier global namespace[2]. As far as list comprehensions, I tend to find list comprehensions the readable and self documenting, at least in Python where I most commonly see them. If nothing else, what is the ordering of the arguments for the equivalent non list comprehension? With list comprehensions you don't have that impedance. // Python example with filter vs list comprehension // Filter requires you to remember the ordering -- // and does it filter on True or False? filter(lambda x: x % 2 == 0, range(10)) --> 0 2 4 6 8 // The list comprehension is self documenting [x for x in range(10) if x % 2 == 0] --> 0 2 4 6 8 I can also convert the majority of list comprehensions into English quite easily -- "output x for each x in range(10) if x is divisible by 2" (though it may be cleaner if it was "for each x in range(10) [output x] if x is divisible by 2"). [1]: http://php.net/quickref.php http://php.net/quickref.php [2]: http://docs.python.org/library/functions.html http://docs.python.org/library/functions.html + http://docs.python.org/library/exceptions.html http://docs.python.org/library/exceptions.html
  - MarceloRamos 14y ago
    Yes what the code does is very clear, but the function call is even a level up clearer, maybe you don't want to know how it does it's job, you just want an array of values in a column (array_column(array, column)). Personally I like comprehensions, but I tend to disguise them behind a function, it's much more clear to me. (but if I need the code to be super fast, I avoid using an extra function.)
drcongo 14y ago
Keyword args would make such a huge difference. +1 to that.
devgutt 14y ago
I can't say I like the solution for parameter skipping though... I disagree with the author -- many optional arguments is not a problem IMO This is a problem and bad design, because instead of default arguments you can use properties for optional arguments.
- swivelmaster 14y ago
  Or encapsulate excess arguments in objects that represent the data that needs to be moved around, if possible.
- smsm42 14y ago
  You can, but: some function already exist with existing APIs - especially in libraries and existing internal PHP functions - and currently there's no way to say "I want default for the second parameter, but non-default for the third", unless you copy-paste the default from the docs.
fleitz 14y ago
array_column looks like a half-assed version of map. Looks like PHP hasn't changed a bit. Functions that do half of what their supposed to do and have odd names that depart wildly from industry standard language.
- maratd 14y ago
  > have odd names that depart wildly from industry standard language Err... what? You want map, use map. http://us3.php.net/manual/en/function.array-map.php http://us3.php.net/manual/en/function.array-map.php
- ricardobeat 14y ago
  to be fair he did mention array_pluck, but the odds are for the most awkward name.
rmccue 14y ago
Agreed on keyword args. I maintain Requests for PHP [1] which has a very similar API to Python Requests, and at the moment, you have to use an array as the options parameter. $options = ['timeout' => 0.5]; $r = Requests::get('https://api.github.com/', $headers, $data, $options); [1]: http://requests.ryanmccue.info/ http://requests.ryanmccue.info/
smsm42 14y ago
I do not believe you can improve generic list comprehension/generator system to a level it would have the speed of a specialized C function, unless you make a special case in the compiler which would effectively call such function instead of actually generating the code as written.

by Smerity 14y ago

conradfr 14y ago

I, for one, never understood why there was no "default" keyword available, but the python example is great as well. About the rest of the article : - the modified empty() is nice, while I still think this function accepts to much thing as empty, or at least should be more flexible. Getter/setter : finally. Now I don't get why there is no readonly keyword which would put the variable as readonly only for the class' outer world.

shakesbeard 14y ago
The article clearly states that there are more features like a read-only keyword. https://wiki.php.net/rfc/propertygetsetsyntax-as-implemented https://wiki.php.net/rfc/propertygetsetsyntax-as-implemented
- jasonlotito 14y ago
  That's not what he's referring to. He's specifically referring to a read-only that only affects external classes. So, the object itself could write to that field, but nothing else could.
  - shakesbeard 14y ago
    You can set the visibility of both the properties and the getters/setters. class Foo { private $fuzz; protected $Bar { get { return $this->fuzz; } private set { $this->fuzz = $value; } } }
    - jasonlotito 14y ago
      Yes. I understand that. My point was just that he specifically wanted a read-only.

RobAley 14y ago

I agree with you on using keyword arguments, it makes it more obvious (and where there are many optional parameters, may save some typing!). With regards to the array_column function, PHP has a history of providing such functions for common operations, even where the same functionality can be replicated with more generic code constructs. For me, the function example you provide is more readable than the comprehension example, requires less typing and provides less room for mistakes. I.E. its simpler in this case, and that’s part of the way PHP rolls. There is of course an argument that functions like this should be provided by external libraries or frameworks rather than in the core of the language, but that debate has been had many times and PHP has come down on the side of including them. This is one of the reasons developers like me like PHP. YMMV.

frosas 14y ago

I agree keyword arguments are a better solution (but probably harder to implement). Right now this is how I do this: function salute($user, array $options = null) { $options = (array) $options + array('shout' => false); $salutation = "Hi $user!"; if ($options['shout']) $salutation = strtoupper($salutation); return $salutation; }

smsm42 14y ago
It is significantly harder to implement, especially if you think about what happens with existing functions, especially internal ones.

geon 14y ago

> I'm not sure why they're adding the array_column function Isn't the function call much more readable than the comprehension? At least as a beginner, I found the large set of built in functions to be one of the strongest points of PHP.

Smerity 14y ago
One major disadvantage with so many functions is the cluttered global namespace[1]. PHP only added namespaces in 5.3.0 and can't modularize their globals into namespaces without causing massive backwards compatibility problems. PHP is stuck with a polluted global namespace, I'd be wary of adding more. Mind you, I'm well aware that this feeling could just be as I'm primarily a Python coder -- in PHP, you perform array_keys($xyz) whilst in Python it's xyz.keys(). Whilst you might consider Python as cheating by pushing all the functions onto the objects, it results in a far happier global namespace[2]. As far as list comprehensions, I tend to find list comprehensions the readable and self documenting, at least in Python where I most commonly see them. If nothing else, what is the ordering of the arguments for the equivalent non list comprehension? With list comprehensions you don't have that impedance. // Python example with filter vs list comprehension // Filter requires you to remember the ordering -- // and does it filter on True or False? filter(lambda x: x % 2 == 0, range(10)) --> 0 2 4 6 8 // The list comprehension is self documenting [x for x in range(10) if x % 2 == 0] --> 0 2 4 6 8 I can also convert the majority of list comprehensions into English quite easily -- "output x for each x in range(10) if x is divisible by 2" (though it may be cleaner if it was "for each x in range(10) [output x] if x is divisible by 2"). [1]: http://php.net/quickref.php http://php.net/quickref.php [2]: http://docs.python.org/library/functions.html http://docs.python.org/library/functions.html + http://docs.python.org/library/exceptions.html http://docs.python.org/library/exceptions.html
- MarceloRamos 14y ago
  Yes what the code does is very clear, but the function call is even a level up clearer, maybe you don't want to know how it does it's job, you just want an array of values in a column (array_column(array, column)). Personally I like comprehensions, but I tend to disguise them behind a function, it's much more clear to me. (but if I need the code to be super fast, I avoid using an extra function.)

drcongo 14y ago

Keyword args would make such a huge difference. +1 to that.

devgutt 14y ago

I can't say I like the solution for parameter skipping though... I disagree with the author -- many optional arguments is not a problem IMO This is a problem and bad design, because instead of default arguments you can use properties for optional arguments.

swivelmaster 14y ago
Or encapsulate excess arguments in objects that represent the data that needs to be moved around, if possible.
smsm42 14y ago
You can, but: some function already exist with existing APIs - especially in libraries and existing internal PHP functions - and currently there's no way to say "I want default for the second parameter, but non-default for the third", unless you copy-paste the default from the docs.

fleitz 14y ago

array_column looks like a half-assed version of map. Looks like PHP hasn't changed a bit. Functions that do half of what their supposed to do and have odd names that depart wildly from industry standard language.

maratd 14y ago
> have odd names that depart wildly from industry standard language Err... what? You want map, use map. http://us3.php.net/manual/en/function.array-map.php http://us3.php.net/manual/en/function.array-map.php
ricardobeat 14y ago
to be fair he did mention array_pluck, but the odds are for the most awkward name.

rmccue 14y ago

Agreed on keyword args. I maintain Requests for PHP [1] which has a very similar API to Python Requests, and at the moment, you have to use an array as the options parameter. $options = ['timeout' => 0.5]; $r = Requests::get('https://api.github.com/', $headers, $data, $options); [1]: http://requests.ryanmccue.info/ http://requests.ryanmccue.info/

smsm42 14y ago

I do not believe you can improve generic list comprehension/generator system to a level it would have the speed of a specialized C function, unless you make a special case in the compiler which would effectively call such function instead of actually generating the code as written.