Can PHP dissect its own syntax? For example, I'd like to write a function that takes in an input like $object->attribute and says to itself:

OK, he's giving me $foo->bar, which means he must think that $foo is an object that has a property called bar. Before I try accessing bar and potentially get a 'Trying to get property of non-object' error, let me check whether $foo is even an object.

The end goal is to echo a value if it is set, and fail silently if not.

I want to avoid repetition like this:

<input value="<? if(is_object($foo) && is_set($foo->bar)){ echo $foo->bar; }?> "/>

...and to avoid writing a function that does the above, but has to have the object and attribute passed in separately, like this:

<input value="<? echoAttribute($foo,'bar') ?>" />

...but to instead write something which:

• preserves the object->attribute syntax
• is flexible: can also handle array keys or regular variables

Like this:

<input value="<? echoIfSet($foo->bar); ?> />
<input value="<? echoIfSet($baz['buzz']); ?> />
<input value="<? echoIfSet($moo); ?> />

But this all depends on PHP being able to tell me "what kind of thing am I asking for when I say $object->attribute or $array[$key]", so that my function can handle each according to its own type.

Is this possible?