Add type::is::nil function

[Odonno]

Thank you for submitting this pull request! We really appreciate you spending the time to work on these changes.

What is the motivation?

Add a simple way to check for nullable (not truthy) values.
Note: can be useful for building an ORM.

What does this change do?

Before:

WHERE (value != NONE AND value != null);

After:

WHERE !type::is::nil(value);

What is your testing strategy?

Unit tests

Is this related to any issues?

N/A

Does this change need documentation?

• Add type::is::nil function docs.surrealdb.com#525

Have you read the Contributing Guidelines?

• I have read the Contributing Guidelines

[phughk]

Loving these PRs, thanks!

[tobiemh]

Hi @Odonno thanks for this PR 🎉 ! I've had a proper think about this, and in conclusion, although it does save a little bit of writing, the introduction of this function could be unclear for a number of reasons:

• All of the type::is functions are actual types in SurrealDB. type::is::nil() implies that there is a nil type in the database.
• Languages like Golang have a nil keyword, which might be confusing to users, especially given that there are already NONE and NULL types in SurrealDB.

As a result, I'm going to close this PR, but if you have any additional ideas, then do let me know in a separate issue or pull request!

[Odonno]

Hello Tobie. This is a valid argument. I will try to find a better name.