eval

The eval function is used to run the PHP code that may be present in a string variable. The use of eval proves quite useful when, for example, you need to store pieces of code within a database and then run them on output.

Here's an example comparing to eval echo:

 



 <? Php







 / / Create a simple variable string







 $ Site = "centre-equestre-lepuy.com";









 / / Create a second variable that needs the first







 $ Sentence = '$'re visiting the site';









 / / I try to print the second sentence with echo







 echo $ sentence.

 



 "<br />";









 / / Now try to parse sentences with eval $ ...







 / / I must remember to use the quotes!







 eval ("\ $ sentence = \" $ sentence \ ";");









 / / Mold again to see the effect of eval







 echo $ sentence;







 ?>

 

Following the result of our code:

 $'re Visiting site







 You're visiting centre-equestre-lepuy.com

As you can see the second line (the work of eval) is very different from the first ...