[FEATURE] Support `_/-` as parsed field name

[penghuo]

Is your feature request related to a problem?

The following query failed with SemanticCheckException.

source=test001 | parse message 'endpoint=/(?<action_code>\\w+)' | fields action_code

{
  "error": {
    "reason": "Invalid Query",
    "details": "can't resolve Symbol(namespace=FIELD_NAME, name=action_code) in type env",
    "type": "SemanticCheckException"
  },
  "status": 400
}

What solution would you like?
The query should works successfully.

What alternatives have you considered?
n/a

Do you have any additional context?
Add any other context or screenshots about the feature request here.

[songkant-aws]

I can take a look

[RyanL1997]

Hi @songkant-aws , I saw that you have assigned yourself this issue. And just letting you know this can be covered by the related enhancement I'm currently working on for rex : #4434.

[RyanL1997]

Also, adding some input that me and @penghuo discussed earlier today about this type of known limitations coming from java regex library:

• Reference to the info I gathered here: [Enhancement] Error handling for illegal character usage in java regex named capture group #4434 (comment), _/- cannot be supported due to the java regex limitation.

According to the above, here are some action items / work around that we can do:

• Having a better error handling that check the illegal characters in regex pattern - [Enhancement] Error handling for illegal character usage in java regex named capture group #4434 covered that.
• User should able to use the rename command to work around the naming limitation of capture group, for example:

curl -X POST "localhost:9200/_plugins/_ppl" \
    -H "Content-Type: application/json" \
    -d '{
      "query": "source=accounts | rex field=email \".+@(?<domain>.+)\" | rename domain as domain_name | fields email, domain_name | head 5"
    }'

{
  "schema": [
    {
      "name": "email",
      "type": "string"
    },
    {
      "name": "domain_name",
      "type": "string"
    }
  ],
  "datarows": [
    [
      "amberduke@pyrami.com",
      "pyrami.com"
    ],
    [
      "hattiebond@netagy.com",
      "netagy.com"
    ],
    [
      "nanettebates@quility.com",
      "quility.com"
    ],
    [
      "daleadams@boink.com",
      "boink.com"
    ],
    [
      "elinorratliff@scentric.com",
      "scentric.com"
    ]
  ],
  "total": 5,
  "size": 5
}