What are the advantages of using eval()?

[11Tami]

Hello, would like to know what eval() is good for doing in php? Please don't refer me to the manual, already been there. Need a description in simple terms. Thanks a lot.

[The Little Guy]

it will evaluate a string as a string, and it will not as an executable string. variables will not be used as variables.
[code]
<?php
$string = 'cup';
$name = 'coffee';
$str = 'This is a $string with my $name in it.';
echo $str. "\n";
eval("\$str = \"$str\";");
echo $str. "\n";
?> [/code]

Output:
This is a $string with my $name in it.
This is a cup with my coffee in it.

[11Tami]

Thanks but can you make it more simple for someone who doesn't do scripting all the time? I have no clue what you just said. I know there are many types of strings. I don't see a difference between a string and an executable string.  I believe these are variables $ but everything I saw said eval can use variables. So I don't understand your description. Please explain the difference someone and explain it like your are talking to someone in high school who hasn't done much scripting? Thank you very much.

[utexas_pjm]

eval lets you treat a string like it's valid PHP.  For example:

[code]
$sum = 1 + 1;
echo $sum;
// would print: 2
[/code]

likewise..

[code]
eval('$sum = 1 + 1;');
echo $sum;
// would print 2
[/code]

If you'd like to see some less trivial uses let me know.