PhpBrew\ExtensionList::exists PHP Method

    public function exists($extensionName)
    {
        // determine which provider support this extension
        $providers = $this->getProviders();
        foreach ($providers as $provider) {
            if ($provider->exists($extensionName)) {
                return $provider;
            }
        }
        return false;
    }

 public function execute($extensionName)
 {
     $extensionList = new ExtensionList($this->logger, $this->options);
     $provider = $extensionList->exists($extensionName);
     if ($provider) {
         $extensionDownloader = new ExtensionDownloader($this->logger, $this->options);
         $versionList = $extensionDownloader->knownReleases($provider);
         $this->logger->info("\n");
         $this->logger->writeln(wordwrap(implode(', ', $versionList), 80, "\n"));
     } else {
         $this->logger->info("Can not determine host or unsupported of {$extensionName} \n");
     }
 }