in a wordpress environment this will generate a composer.json string, WIP

gistfile1.php

<?php

function get_composer_json() {
	$plugins = get_plugins();
	$data = array();
	$data['rarst/wordpress'] = '>='.get_bloginfo( 'version' );
	$data['php'] = '>=5.2.4';
	foreach ( $plugins as $plugin ) {
		$key = 'wpackagist/'.sanitize_title( $plugin['Name'] );
		$data[ $key ] = $plugin['Version'];
	}
	$manifest = array();
	$manifest['name'] = 'wpsite/'.sanitize_title( get_bloginfo( 'name' ) );
	$repositories = array();
	$repositories[] = array(
		'type' => 'vcs',
		'url' => 'http://rarst.net'
	);
	$manifest['description'] = get_bloginfo( 'description' );
	$manifest['homepage'] = home_url();
	$manifest['version'] = get_bloginfo( 'version' );
	$manifest['repositories'] = $repositories;
	$manifest['extra'] = array(
		'installer-paths' => array(
			'./' => array( 'rarst/wordpress' )
		)
	);
	$manifest['require'] = $data;
	$json = json_encode( $manifest, ( JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT ) );
	return $json;
}