php cli ast generation

ast.php

#!/usr/bin/env php
<?php

declare(strict_types=1);

define( "AST_PHP_VERSION", 80 );

if( PHP_SAPI !== 'cli' ) {
	exit("Please run as a PHP CLI!");
}

if( ! isset($argv[1]) ) {
	exit("Please provide a file name or string of PHP code as an argument!");
}

if( ! in_array( "ast", get_loaded_extensions() ) ) {
	exit("Please ensure the php/ast module is installed!");
}

$ast = null;
if( is_file( $argv[1] ) ) {
	$ast = ast\parse_file( $argv[1], $version=AST_PHP_VERSION );
}
else if( is_string( $argv[1] ) ) {
	$ast = ast\parse_code( $argv[1], $version=AST_PHP_VERSION );
}
else {
	exit("A file name or valid PHP code string were not provided as an argument!");
}

if( $ast !== null ) {
	echo $ast;
}
else {
	exit("AST unable to be generated!");
}