function applyFormula($formula, $values)
{
$rawFormula = $formula;
$ids = idsPerFormula($formula);
$i = 0;
foreach ($ids as $id) {
if ($values[$i] == "") {
return null;
}
$formula = preg_replace("/\\[#id{$id}\\]/", " " . $values[$i++] . " ", $formula);
}
$result = eval("return {$formula};") or die("<b style=color:red>ERROR IN FORMULA '{$rawFormula}'</b>");
return $result;
}
<?php
/* NEW CALCULATION INSERT TO DB */
//check input
if (!isset($_POST['name'], $_POST['formula'], $_POST['unit'])) {
die;
}
//process input
$name = mysql_real_escape_string($_POST['name']);
$form = mysql_real_escape_string($_POST['formula']);
$unit = mysql_real_escape_string($_POST['unit']);
//check for duplicates in name and formula
$duplicates = current(mysql_fetch_array(mysql_query("SELECT COUNT(*) FROM calculations WHERE name='{$name}'")));
if ($duplicates > 0) {
die("ERROR! This calculation name already exists!");
}
$duplicates = current(mysql_fetch_array(mysql_query("SELECT COUNT(*) FROM calculations WHERE formula='{$form}'")));
if ($duplicates > 0) {
die("ERROR! This calculation formula already exists!");
}
//check if formula is valid
include "calculations_library.php";
$ids = idsPerFormula($form);
$result = applyFormula($form, $ids);
//if it's incorrect, this function will die()
//all is ok! insert calculation query
$sql = "INSERT INTO calculations (name,formula,unit) VALUES ('{$name}','{$form}','{$unit}')";
mysql_query($sql) or die(mysql_error());
//success & go to new device
echo "<b>New Calculation '{$name}' Inserted Correctly!</b> ";
$id = current(mysql_fetch_array(mysql_query("SELECT MAX(id) FROM calculations")));
echo "<a href=calculation.php?id={$id}>VIEW</a>";
#newCalc:hover {background:lightgreen;transition:all 0.5s}
</style>
<b>+ Create New Calculation</b>
</div>
<!--CREATED CALCULATIONS-->
<div style=margin-top:2em>
<table cellpadding=10>
<tr><th>Calculation Name<th>Formula<th>Devices involved<th>Unit<th>Options</tr>
<?php
include 'calculations_library.php';
//to use idsPerFormula()
$sql = "SELECT * FROM calculations";
$res = mysql_query($sql) or die(mysql_error());
echo "<b>" . mysql_num_rows($res) . " calculations found</b>";
while ($row = mysql_fetch_array($res)) {
$id = $row['id'];
$name = $row['name'];
$unit = $row['unit'];
$formula = $row['formula'];
//get devices ids array from formula
$devicesInvolved = count(idsPerFormula($formula));
echo "<tr>\n\t\t\t\t<td><a href=calculation.php?id={$id}>{$name}</a>\n\t\t\t\t<td>{$formula}\n\t\t\t\t<td align=center>{$devicesInvolved}\n\t\t\t\t<td>{$unit}\n\t\t\t\t<td><button onclick=\"if(confirm('Are you sure that you want to delete calculation id {$id}?'))\n\t\t\t\t\t\t\t\t\t{window.location='deleteCalculation.php?id={$id}'}\"\n\t\t\t\t\t\t\tstyle='background:red'>\n\t\t\t\t\t\t\tDelete Calculation</button>";
}
if (mysql_num_rows($res) == 0) {
echo "<tr style=color:#666><td colspan=5>~No calculations created yet";
}
?>
</table>
</div>