An experiment for comparing boolean expressions in PHP

boolean-logic.php

<?php


function toString($value) {
    if ($value === TRUE) return 'TRUE';
    if ($value === FALSE) return 'FALSE';
    if ($value === null) return 'null';
    if (is_string($value)) return '"' . $value . '"';
    return $value;
}

function pick_color($v) {
    if ($v) return 'green'; 
    return 'red';
}

$values = [TRUE, FALSE, 'TRUE', 'FALSE', 1, 0, -1, '1', '0', '-1', 'foo', '', null];



//php -S localhost:3000

?>

<style>
#compare-table {
  font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
  border-collapse: collapse;
  width: 100%;
}

#compare-table td, #compare-table th {
  border: 1px solid #ddd;
  padding: 8px;
}

#compare-table tr:nth-child(even){background-color: #f2f2f2;}

#compare-table tr:hover {background-color: #ddd;}

#compare-table th {
  padding-top: 12px;
  padding-bottom: 12px;
  text-align: left;
  background-color: #4CAF50;
  color: white;
}
</style>


<h1>Using ==</h1>
<table id="compare-table">
<thead>
<tr>
   <th></th>
   <?php 
   foreach ($values as $value) {
       echo '<th>' . toString($value) . '</th>';
   }
   ?>
</tr>
</thead>

<tbody>

<?php 

for ($y = 0; $y < count($values); $y++) {
    echo '<tr>';
    echo '<th>' . toString($values[$y]) . '</th>';
    for ($x = 0; $x < count($values); $x++) {
        echo '<td style="background-color: '. pick_color($values[$y] == $values[$x]) .'">' . toString($values[$y] == $values[$x]) . '</td>';
    }
    echo '</tr>';
}

?>

</tbody>
</table>



<h1>Using ===</h1>
<table id="compare-table">
<thead>
<tr>
   <th></th>
   <?php 
   foreach ($values as $value) {
       echo '<th>' . toString($value) . '</th>';
   }
   ?>
</tr>
</thead>

<tbody>

<?php 

for ($y = 0; $y < count($values); $y++) {
    echo '<tr>';
    echo '<th>' . toString($values[$y]) . '</th>';
    for ($x = 0; $x < count($values); $x++) {
        echo '<td style="background-color: '. pick_color($values[$y] === $values[$x]) .'">' . toString($values[$y] === $values[$x]) . '</td>';
    }
    echo '</tr>';
}

?>

</tbody>
</table>