Running PHP Script as a Python Script [StandAlone Script]

or Tagless script

1. Little slow

Write a Program to print expression based calculation

inorder to solve any expression we can use eval() function

to evaluate a expression as a string

Limitation of using eval()

eval() can be used to evaluate the expression as a string it may contain keyword

or varibles as string

for example

This is valid

$i=10;

eval("if($i==10){echo 'hello';}else{ echo 'hi';}");

php > $i=10;

php > eval("if($i==10){echo 'hello';}else{ echo 'hi';}");

hello

php > $i=8;

php > eval("if($i==10){echo 'hello';}else{ echo 'hi';}");

1. eval() does not support assignment operator if you try to execute this 

then d`code() error is raised since it is parse error no output 

is going to generate.

2. PHP community Itself Discourages the use of eval() 

IT  IS DANGEROUS TO USE EVAL

Advantage:

1.donot allow any script specially to run enclosed as <?php tag ?>

2. using eval() expression you donot required wrapper tags or Tag Container

ie is you need not wrap your code inside <?php Tag ?>

Example :

<?php echo 'Hello world' ?>

eval("<?php echo 'hello world'; ?>");

parse Error unexpected Eol at line no something unexecpted '<'