tree c6a420fc5b0fb793a7fde8bf8af90c4ca12a29bf
parent f7d85016586207b36585b199f6b867a95267f27d
author Igor Ryzhov <iryzhov@nfware.com> 1633427307 +0300
committer Michal Vasko <mvasko@cesnet.cz> 1633428436 +0200

parser BUGFIX allow empty pattern

Empty regular expression is explicitly allowed by the standard:

```
+---------------------------------+----------------------------------+
| For all branches S, and for all | Denoting the set of strings L(R) |
| regular expressions T, valid    | containing:                      |
| regular expressions R are:      |                                  |
+---------------------------------+----------------------------------+
| (empty string)                  | the set containing just the      |
|                                 | empty string                     |
+---------------------------------+----------------------------------+
| S                               | all strings in L(S)              |
+---------------------------------+----------------------------------+
| S|T                             | all strings in L(S) and          |
|                                 | and all strings in L(T)          |
+---------------------------------+----------------------------------+
```

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>