Nested attribute acccess

Brief summary of issue / Description of requested feature:

When using complex data types on object attrs, accessing nested keys/indexes would be awesome.

Steps to reproduce the issue / Reasons for adding feature:

1. set here/test_list = ['this', 'that', 'the other']
2. set here/test_list/0

Error output / Expected result of feature

Expected: Attribute Location Name/test_list/0 = this Actual: Attribute Location Name/test_list = ['This', 'that', 'the other'] Location Name has no attribute '0'.

Extra information, such as Evennia revision/repo/branch, operating system and ideas for how to solve / implement:

Looks like search_for_obj in evennia/commands/default/building.py would be the place to implement this chained attr lookup. Shouldn’t be too hard to implement, but would break folks expecting the multiple attr lookup, so it might need some new semantics/command.

I’m happy to attempt a PR if there is consensus on the interface.

[aarcro]

Perfect. Yes, would have to parse and sanitize ourself, not eval. We’d probably want to check for the exact name before attempting nested access, just in case there’s an existing attribute with [] in the name.

On Sun, Sep 15, 2019, 8:02 AM Griatch [e-mail] wrote:

@aarcro https://github.com/aarcro This would make the set command a lot more powerful and would be a useful addition. I have some comments on the syntax though, should you feel like trying your hand at an implementation.

When coming to these kind of operations you are accessing Python structures stored in the Attribute. So I think it may be better and more intuitive to use Python syntax for it and implement this kind of operation just the way as you would expect in Python - that is, a syntax like

set here/test_list[0] = ‘foo’ set here/test_dict[‘bar’] = 32342 set here/test_dict_list[‘bar’][4] = ‘test’

One key thing to remember with any such implementation is that Python eval or exec must never be used to perform the operation - this would be a major security issue (making set possible to make work as the py command). Rather, the [ ] argument must be manually parsed and the content used to query the value in the Attribute, relaying proper, sanitized errors to the user.

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[aarcro]

The other option is to take insert/append out completely, but then you can only add to a list by copy/pasting the value and editing, the same as today.