PHP: What are language constructs and why do we need them?

Question

I keep coming across statements like:

• \"echo is a language construct but print is a function and hence has a return value\"
• \"die is a language constr

Answer 1

Some things are just not possible using normal functions, consider this snippet:

list($el1, $el2) = array('el1', 'el2');

What it does is it takes the elements from a non-associative array and assigns the values to the variables defined in the list() construct.

Simply cannot be done with functions :)

A more subtle example is issetand empty. Though they look like functions, they one thing that's not possible with functions alone – they do not generate "variable is undefined" or "undefined index" notices.