Compare PHP values for truthiness - to generate http://i.imgur.com/B8R3PVK.png

values.dot

graph values {
    "''" -- "0"
    "''" -- "0.0"
    "''" -- "false"
    "''" -- "null"
    "'0'" -- "'0.0'"
    "'0'" -- "0"
    "'0'" -- "0.0"
    "'0'" -- "false"
    "'0.0'" -- "0"
    "'0.0'" -- "0.0"
    "'0.0_'" -- "0"
    "'0.0_'" -- "0.0"
    "'1'" -- "'1.0'"
    "'1'" -- "1"
    "'1'" -- "1.0"
    "'1.0'" -- "1"
    "'1.0'" -- "1.0"
    "'1.0_'" -- "1"
    "'1.0_'" -- "1.0"
    "'<p/>'" -- "0"
    "'<p/>'" -- "0.0"
    "'<p>1</p>'" -- "0"
    "'<p>1</p>'" -- "0.0"
    "'<p>php</p>'" -- "0"
    "'<p>php</p>'" -- "0.0"
    "'php'" -- "0"
    "'php'" -- "0.0"
    "'_0'" -- "0"
    "'_0'" -- "0.0"
    "'_0.0'" -- "0"
    "'_0.0'" -- "0.0"
    "'_0.0_'" -- "0"
    "'_0.0_'" -- "0.0"
    "'_1'" -- "0"
    "'_1'" -- "0.0"
    "'_1.0'" -- "0"
    "'_1.0'" -- "0.0"
    "'_1.0_'" -- "0"
    "'_1.0_'" -- "0.0"
    "0" -- "0.0"
    "0" -- "false"
    "0" -- "null"
    "0.0" -- "false"
    "0.0" -- "null"
    "1" -- "1.0"
    "array()" -- "false"
    "array()" -- "null"
    "false" -- "null"
}

values.php

<?php
$values = array(
    array("''", ''),
    array("'0'", '0'),
    array("'0.0'", '0.0'),
    array("'0.0_'", '0.0_'),
    array("'1'", '1'),
    array("'1.0'", '1.0'),
    array("'1.0_'", '1.0_'),
    array("'<p/>'", '<p/>'),
    array("'<p>1</p>'", '<p>1</p>'),
    array("'<p>php</p>'", '<p>php</p>'),
    array("'php'", 'php'),
    array("'_0'", '_0'),
    array("'_0.0'", '_0.0'),
    array("'_0.0_'", '_0.0_'),
    array("'_1'", '_1'),    
    array("'_1.0'", '_1.0'),
    array("'_1.0_'", '_1.0_'),
    array("0", 0),
    array("0.0", 0.0),
    array("1", 1),
    array("1.0", 1.0),
    array("array()", array()),
    array("false", false),
    array("null", null),
);
$valuesTotal = count($values);

echo "graph values {\n";    
for ($i = 0; $i < ($valuesTotal - 1); $i++) {
    foreach (range($i + 1, $valuesTotal - 1) as $k) {
        list($baseDisplay, $base) = $values[$i];
        list($compareDisplay, $compare) = $values[$k];
        // echo "$i:$k Checking $baseDisplay == $compareDisplay: ";
        // echo ($base == $compare)?"TRUE\n":"FALSE\n";
        if ($base == $compare) {
            echo '"' . $baseDisplay . '" -- "' . $compareDisplay . '"' . "\n";            
        }
    }
}
echo "}\n";