STIX Patterning needs to support basic dictionary operations

[treyka]

function	description
isin	isin(x,y) [Is a key present in the dictionary?]

[gtback]

Can this be a new operator like CONTAINSKEY or HASKEY?

[jordan2175]

We talked about this on 2019-06-05. We currently have dictionaries in STIX objects and we have no way to look inside them. HTTP Headers is a dictionary, but you can not check if a specific HTTP Header exists. This is looking at the dictionary key. You can not check to see if a certain key is in the dictionary. This is a gap in patterning right. We think this should be done in 2.1. But we need to find someone to implement this in the spec.