php_constants.php

/**
 * Static variables keep their value after function calls.
 * useful for making counters to track number of function calls.
 * bc $count has already been declared, initialization is skipped.
 * it retains previous value, then is incremented and is displayed w new value.
 *
 * can only be assigned w predetermined value.
 * cannot assign the result of an expression.
 */
function test() {
	static $count = 0;
	echo '<p>$count is: ' . $count . '</p>';
	++$count;
}
test();
test();
test();
test();