PSR 4 error

In my laravel project I did:

```
composer require jcubic/expression
```

And I got the error:

```
Class jcubic\Parser located in ./vendor/jcubic/expression/src/jcubic/Parser.peg.php does not comply with psr-4 autoloading standard. Skipping.

```

Is that an issue????

Another error that I got is:

```
Skipped installation of bin bin/peg for package smuuf/php-peg: file not found in pack
```