Type hints with null default values

Marcus Boerger wrote:

Hello Robert,

Tuesday, October 19, 2004, 10:20:59 PM, you wrote:

The issues surrounding this seemed to have been muddied up a little, I'll
try to clear them up.

I see two different sets of functionality that people are asking for.

#1. The ability to pass null on a type hinted param (but still a
#mandatory
param)

#2. The ability to define an optional type hinted param.

I see it as a very important distinction to make. Using the #2 to solve
#1 is not the solution PHP should implement. Using some method which
operates on the class hint itself is the right solution.

For example, using the [] method:

public function Compare([BaseClass] $objA, $cmpFunc);

As far as we disallow this and only allow optional types at the end i'd
agre to this. Example:

public function Compare($cmpFunc, [BaseClass] $objA);

I don't see any danger if we allow null with this syntax:

 public function Compare([BaseClass] $objA, $cmpFunc);

if we don't allow null with this syntax:

 public function Compare(BaseClass $objA, $cmpFunc);

and if we make an argument optional with this syntax:

 public function Compare($cmpFunc, BaseClass $objA=null);

If someone (like me) has thousands lines of code that uses 'null' meaning
'null reference' just need to use syntax #1.

If someone is very strict and don't even think about using null in
typehinted arguments, because null is not a value it's a type and must be
used as so, just need to use syntax #2.

If someone wants to make typehinted parameters optional, just use syntax #3.

I really don't see any problem allowing this three syntaxes(but I'm not very
clever since I'm for syntax #1) :-P

Regards,

Cristiano Duarte

Marcus Boerger wrote:

So for now the only addition we may probably consider for 5.1 is
adding 4: optional typehinted values that default to null and only
null.

Please don't add another parameter syntax (especially with line-noi...
err special characters) like [BaseClass]. This would make PHP more
unreadable than it needs to be for a minor feature. To allow
foo(BaseClass $objA = null) to also accept foo(null); handles the few
cases where you want to pass null nicely IMHO.

Advocating to only change the PHP syntax to simplify it,

• Chris

Marcus Boerger wrote:

So for now the only addition we may probably consider for 5.1 is
adding 4: optional typehinted values that default to null and only
null.

That sounds like the most sane way to do it.

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Sebastian Bergmann http://www.sebastian-bergmann.de/
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