Argument coercion into HashSet/BTreeSet

[kakserpom]

PR — #598

Description

pub fn tags(&mut self, tags: HashSet<&str>) would be nice. Now you have to either deal with Zval directly or use Vec and then convert Vec into HashSet.

Additional Context

• I can try implementing this feature myself (please assign me to this issue)

[Xenira]

What would the php be for this? Take an array and turn it into a HashSet?

[kakserpom]

Not sure.

[kakserpom]

Yes, take an array (asserting that has_sequential_keys() is true) and turn into a HashSet.

[kakserpom]

@Xenira I've deliberately not included the said has_sequential_keys() check in the PR, I thought the keys can be ignored altogether. What do you think?