function - PHP - eval code from DB -

there have been hundreds if not thousands of posts concerning use of php's eval(); run code database. through searching have not found answer question (explained shortly).

firstly i'll introduce application.

i have 3 records of valid code stored in database:
eg:
['code1']

$num1 = 1; $num2 = 3; $num3 = $num1+$num2;  //4 

['code2']

$num4 = $num3;        //4 $num5 = 5; $num6 = $num4+$num5;  //9 

['code3']

$num7 = $num4;        //4 $num8 = $num6;        //9 $num9 = $num7+$num8;  //13 echo $num9;           //13 

next have function call , run record:
eg:

function runcode($codename) {     // assume db connection established     $result = mysql_query("select `code` codestore `name` = '".$codename."'");     if ($result) {         // fetch 1 row         $row = mysql_fetch_assoc($result);         if (!$row) {             die('no rows returned.');         } else {             return eval($row['code']);         }     } else {         die('invalid query: '.mysql_error());     } } 

now, needs happen call 3 above snippets, 1 after each other, , have variables inside ($numx) available use between each other.
eg:

runcode('code1'); runcode('code2'); runcode('code3'); 

the above call of 3 snippets db should echo '13', not. , there question:

how can make these variables available outside eval'd code?

variables db local in function. make them global.

so may use global keyword change variables scope:

<?php error_reporting (e_all);  $txt = array( '$num1 = 1; $num2 = 3; global $num3; // make global, used later $num3 = $num1+$num2; echo "num3=" . $num3 . "<br>"; //4',  'global $num3; // need use value var global $num4; // make global, used later $num4 = $num3;        //4 $num5 = 5; global $num6; // make global, used later $num6 = $num3+$num5;  echo "num6=" . $num6 . "<br>"; //9',  'global $num4; // need use value var global $num6; // need use value var $num7 = $num4;        //4 $num8 = $num6;        //9 global $num9; // make global, used later (maybe) $num9 = $num7+$num8;  //13 echo "num9=" . $num9 . "<br>";           //13' );  function runcode($codename) { // example     eval($codename); }  runcode($txt[0]); runcode($txt[1]); runcode($txt[2]); ?> 

this solution demands changing existing code in db. may difficult.

so, here different algorithm. @ first, join code chunks together. run eval function , pass joined code it. example:

function composecode($codename) {     // assume db connection established     $result = mysql_query("select `code` codestore `name` = '".$codename."'");     if ($result) {         // fetch 1 row         $row = mysql_fetch_assoc($result);         if (!$row) {             die('no rows returned.');         } else {             return $row['code']; // changed original code         }     } else {         die('invalid query: '.mysql_error());     } } $code = ''; $code .= composecode('code1'); $code .= composecode('code2'); $code .= composecode('code3'); eval($code);