[PHP] new $foo-className(); Class name must be a valid object or a string
I am trying to load PHP objects stored in a database, where the class
name is stored in a column:
$object = new $resultSet-getString(1);
This fails for the same reason that the following fails:
?php
class Foo
{
public function className()
{
return 'Foo';
}
}
$foo = new Foo;
$bar = new $foo-className();
Fatal error: Class name must be a valid object or a string in test.php
on line 12
I guess this error is due to the confusion of parsing () as the
argument list for the className function, or the Foo constructor...
I work around this error by using a temp variable:
$tmp = $foo-className(); $bar = new $tmp;
- however the above reads like hacky code : (
When calling dynamically named functions, I generally use
call_user_func() to avoid awkwardness with $object-$tmp($arg1, ...)
In other words, I prefer:
call_user_func(array($object, 'get'.$someName), $arg1, ...);
- to:
$tmp = 'get'.$someName; $object-$tmp($arg1, ...);
However there does not appear to be an analog of call_user_func() for
constructing new instances of dynamically named classes?
If I recall correctly, there was also a way to work around calling
dynamically named functions (e.g. $object-$tmp($arg1, ...);) using
curly braces:
$object-{'get'.$someName}($arg1, ...);
- however I cannot recall the exact syntax.
Can anyone confirm that there is a curly brace syntax for calling
dynamically named functions? Could it be applied to instantiating
dynamically named classes?
Can anyone recommend a cleaner alternative to:
$tmp = $foo-className(); $bar = new $tmp;
Thanks and best wishes, Jack
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Re: [PHP] new $foo-className(); Class name must be a valid object or a string
On 4 May 2008, at 00:46, Jack Bates wrote:
I am trying to load PHP objects stored in a database, where the class
name is stored in a column:
$object = new $resultSet-getString(1);
This fails for the same reason that the following fails:
?php
class Foo
{
public function className()
{
return 'Foo';
}
}
$foo = new Foo;
$bar = new $foo-className();
I would rather have a factory method that returns a new instance of
the class. There's no need for the outside world to know the class name.
?php
class Foo
{
public function newInstance()
{
return new self();
}
public function test($a)
{
echo 'test: '.$a.\n;
}
}
$foo = new Foo;
$foo-test('foo');
$bar = $foo-newInstance();
$bar-test('bar');
?
However, if you insist on doing it your way can I make a small
suggestion? It's better to spend your time on functionality rather
than finding ways to save some typing. I see no reason to try to
combine the two statements - saving typing and a pitiful amount of
disk space are the only benefits.
-Stut
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Re: [PHP] new $foo-className(); Class name must be a valid object or a string
On May 3, 2008, at 4:46 PM, Jack Bates [EMAIL PROTECTED] wrote:
I am trying to load PHP objects stored in a database, where the class
name is stored in a column:
$object = new $resultSet-getString(1);
This fails for the same reason that the following fails:
?php
class Foo
{
public function className()
{
return 'Foo';
}
}
$foo = new Foo;
$bar = new $foo-className();
Fatal error: Class name must be a valid object or a string in test.php
on line 12
I guess this error is due to the confusion of parsing () as the
argument list for the className function, or the Foo
constructor...
I work around this error by using a temp variable:
$tmp = $foo-className(); $bar = new $tmp;
- however the above reads like hacky code : (
When calling dynamically named functions, I generally use
call_user_func() to avoid awkwardness with $object-$tmp($arg1, ...)
In other words, I prefer:
call_user_func(array($object, 'get'.$someName), $arg1, ...);
- to:
$tmp = 'get'.$someName; $object-$tmp($arg1, ...);
However there does not appear to be an analog of call_user_func() for
constructing new instances of dynamically named classes?
If I recall correctly, there was also a way to work around calling
dynamically named functions (e.g. $object-$tmp($arg1, ...);) using
curly braces:
$object-{'get'.$someName}($arg1, ...);
- however I cannot recall the exact syntax.
Can anyone confirm that there is a curly brace syntax for calling
dynamically named functions? Could it be applied to instantiating
dynamically named classes?
Can anyone recommend a cleaner alternative to:
$tmp = $foo-className(); $bar = new $tmp;
Thanks and best wishes, Jack
Does...
?php
$bar = new $foo-className()();
?
...work?
Otherwise, I'd just do...
?php
$className = $foo-className();
$bar = new $className;
?
...instead of $tmp.
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