yo::sets

Struct Set

pub struct Set { /* private fields */ }

Expand description

One set, with its key held for you.

This is 15 section 2’s shape: the name is spelled where the handle is made and nowhere else, so a typo is one compile error at one line instead of a lookup that quietly misses at three call sites.

let db = yo::open(yo::MEMORY)?;
let online = db.set("online");

online.add("alice")?;
online.add("bob")?;
assert!(online.contains("alice")?);
assert_eq!(online.len()?, 2);

online.remove("alice")?;
assert!(!online.contains("alice")?);

Implementations§

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impl Set

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pub fn key(&self) -> &[u8] ⓘ

The key this handle holds.

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pub fn add(&self, member: impl AsRef<[u8]>) -> Result<bool>

Add one member, and say whether it was new. SADD.

§Errors

As Sets::add.

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pub fn add_many<M: AsRef<[u8]>>(&self, members: &[M]) -> Result<usize>

Add several members, and say how many were new.

§Errors

As Sets::add.

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pub fn remove(&self, member: impl AsRef<[u8]>) -> Result<bool>

Remove one member, and say whether it was there. SREM.

§Errors

As Sets::add.

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pub fn remove_many<M: AsRef<[u8]>>(&self, members: &[M]) -> Result<usize>

Remove several members, and say how many were there.

§Errors

As Sets::add.

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pub fn contains(&self, member: impl AsRef<[u8]>) -> Result<bool>

Whether a member is in the set. SISMEMBER.

§Errors

As Sets::add.

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pub fn contains_many<M: AsRef<[u8]>>(&self, members: &[M]) -> Result<Vec<bool>>

Whether each of several members is in the set, in the order asked. SMISMEMBER.

§Errors

As Sets::add.

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pub fn len(&self) -> Result<usize>

How many members it holds. SCARD.

§Errors

As Sets::add.

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pub fn is_empty(&self) -> Result<bool>

Whether it holds nothing, which is also true of a key that is not there.

§Errors

As Sets::add.

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pub fn members(&self) -> Result<Vec<Vec<u8>>>

Every member, owned. SMEMBERS.

An empty Vec for a key that is not there. Sets::members is the version that tells the two apart, and this one does not because a handle on a key that was never written to is the ordinary way to start.

§Errors

As Sets::add.

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pub fn for_each(&self, f: impl FnMut(Member<'_>)) -> Result<()>

Hand every member to f where it lies, allocating nothing.

§Errors

As Sets::add.

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pub fn pop(&self) -> Result<Option<Vec<u8>>>

Take one member out at random. SPOP.

§Errors

As Sets::add.

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pub fn pop_n(&self, count: usize) -> Result<Vec<Vec<u8>>>

Take up to count distinct members out at random. SPOP key count.

§Errors

As Sets::add.

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pub fn pick(&self) -> Result<Option<Vec<u8>>>

Draw one member and leave it in the set. SRANDMEMBER.

§Errors

As Sets::add.

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pub fn pick_n(&self, count: i64) -> Result<Vec<Vec<u8>>>

Draw count members and leave them in the set. SRANDMEMBER key count.

§Errors

As Sets::add.

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pub fn move_to(&self, to: &Set, member: impl AsRef<[u8]>) -> Result<bool>

Move one member into another set, and say whether it moved. SMOVE.

§Errors

As Sets::add, and Code::Invalid when to belongs to a different database.

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pub fn intersect(&self, others: &[&Set]) -> Result<Vec<Vec<u8>>>

Everything in this set and in all of others. SINTER.

let db = yo::open(yo::MEMORY)?;
let a = db.set("a");
let b = db.set("b");
a.add_many(&["x", "y"])?;
b.add_many(&["y", "z"])?;

assert_eq!(a.intersect(&[&b])?, vec![b"y".to_vec()]);