for generating stubs for a loaded extension

document.php

<?php
/*
 usage: php document.php --ext name [--output document.txt]
*/
function prototype(Reflector $reflector) {
	$elements = [];

	switch (get_class($reflector)) {
		case "ReflectionClass":
			if ($reflector->isFinal()) {
				$elements[] = "final";
			}

			$elements[] = "class";
			$elements[] = $reflector->getName();

			if ($interfaces = $reflector->getInterfaces()) {
				$elements[] = "implements";

				foreach ($interfaces as $interface => $r)
					$ifs[] = $interface;
				$elements[] = implode(", ", $ifs);
			}

			if ($parent = $reflector->getParentClass()) {
				$elements[] = "extends";
				$elements[] = $parent->getName();
			}
		break;

		case "ReflectionProperty":
			if ($reflector->isPublic()) {
				$elements[] = "public";
			} else if ($reflector->isProtected()) {
				$elements[] = "protected";
			} else {
				$elements[] = "private";
			}

			if ($reflector->isStatic()) {
				$elements[] = "static";
			}

			$elements[] = sprintf("\$%s", $reflector->getName());
		break;

		case "ReflectionParameter":
			if ($type = $reflector->getType()) {
				$elements[] = (string) $type;
			}

			$elements[] = sprintf("\$%s", $reflector->getName());
		break;

		case "ReflectionMethod":
			if ($reflector->isFinal()) {
				$elements[] = "final";
			}

			if ($reflector->isPublic()) {
				$elements[] = "public";
			} else if ($reflector->isProtected()) {
				$elements[] = "protected";
			} else {
				$elements[] = "private";
			}
			if ($reflector->isStatic()) {
				$elements[] = "static";
			}
			/* intentional fall through */

		case "ReflectionFunction":

			$elements[] = "function";
			$elements[] = $reflector->getName();
			$elements[] = "(";
			$ps = [];
			foreach ($reflector->getParameters() as $parameter)
				$ps[] = prototype($parameter);
			$elements[] = implode(", ", $ps);
			$elements[] = ")";
			if ($return = $reflector->getReturnType()) {
				$elements[] = ":";
				$elements[] = (string) $return;
			}
		break;
	}
	return implode(" ", $elements);
}

function document(array $config, Reflector $reflector, ?Reflector $parent, $output) {
	switch (get_class($reflector)) {
		case "ReflectionExtension":
			foreach ($reflector->getConstants() as $name => $constant)
				fprintf($output, "const %s;\n", $name);
			foreach ($reflector->getClasses() as $class)
				document($config, $class, $reflector, $output);
			foreach ($reflector->getFunctions() as $function)
				document($config, $function, $refllector, $output);
		break;

		case "ReflectionClass":
			fprintf($output, "%s {\n", prototype($reflector));
			foreach ($reflector->getConstants() as $name => $constant)
				fprintf($output, "\tconst %s;\n", $name);
			foreach ($reflector->getProperties(REFLECTIONPROPERTY::IS_STATIC) as $property)
				document($config, $property, $reflector, $output);
			foreach ($reflector->getProperties(ReflectionProperty::IS_PUBLIC) as $property)
				document($config, $property, $reflector, $output);
			foreach ($reflector->getProperties(ReflectionProperty::IS_PROTECTED) as $property)
				document($config, $property, $reflector, $output);
			foreach ($reflector->getProperties(ReflectionProperty::IS_PRIVATE) as $property)
				document($config, $property, $reflector, $output);
			foreach ($reflector->getMethods() as $method)
				document($config, $method, $reflector, $output);
			fprintf($output, "}\n");
		break;

		case "ReflectionProperty":
			if ($reflector->getDeclaringClass()->getName() == $parent->getName())
				fprintf($output, "\t%s;\n", prototype($reflector));
		break;

		case "ReflectionMethod":
			if ($reflector->getDeclaringClass()->getName() == $parent->getName())
				fprintf($output, "\t%s;\n", prototype($reflector));
		break;

		case "ReflectionFunction":
			fprintf($output,"%s;\n", prototype($reflector));
		break;
	}
}

$config = [
	"exec" => array_shift($argv),
	"ext" => null,
	"output" => "document.txt",
	"flags" => []
];

while ($arg = array_shift($argv)) {
	switch ($arg[0]) {
		case "-": switch ($arg[1]) {
			case "-":
				$config[substr($arg, 2)] = array_shift($argv);
			break;
			
			default:
				$config["flags"][substr($arg, 1)] = true;
		}
	}
}

if (!$config["ext"] || !extension_loaded($config["ext"])) {
	throw new \RuntimeException(
		$config["ext"] ? 
			"{$config["ext"]} not loaded" : 
			"no extension specified");
}

$output = fopen($config["output"], "w+");

if (!$output) {
	throw new \RuntimeException(
		"could not open {$config["output"]} for writing");
}

document($config, new ReflectionExtension($config["ext"]), null, $output);

fclose($output);
?>

Excellent