interface redis {
  /// Errors related to interacting with Redis
  variant error {
      /// An invalid address string
      invalid-address,
      /// There are too many open connections
      too-many-connections,
      /// A retrieved value was not of the correct type
      type-error,
      /// Some other error occurred
      other(string),
  }

  resource connection {
    /// Open a connection to the Redis instance at `address`.
    open: static func(address: string) -> result<connection, error>;

    /// Publish a Redis message to the specified channel.
    publish: func(channel: string, payload: payload) -> result<_, error>;

    /// Get the value of a key.
    get: func(key: string) -> result<option<payload>, error>;

    /// Set key to value.
    ///
    /// If key already holds a value, it is overwritten.
    set: func(key: string, value: payload) -> result<_, error>;

    /// Increments the number stored at key by one.
    ///
    /// If the key does not exist, it is set to 0 before performing the operation.
    /// An `error::type-error` is returned if the key contains a value of the wrong type
    /// or contains a string that can not be represented as integer.
    incr: func(key: string) -> result<s64, error>;

    /// Removes the specified keys.
    ///
    /// A key is ignored if it does not exist. Returns the number of keys deleted.
    del: func(keys: list<string>) -> result<u32, error>;

    /// Add the specified `values` to the set named `key`, returning the number of newly-added values.
    sadd: func(key: string, values: list<string>) -> result<u32, error>;

    /// Retrieve the contents of the set named `key`.
    smembers: func(key: string) -> result<list<string>, error>;

    /// Remove the specified `values` from the set named `key`, returning the number of newly-removed values.
    srem: func(key: string, values: list<string>) -> result<u32, error>;

    /// Execute an arbitrary Redis command and receive the result.
    execute: func(command: string, arguments: list<redis-parameter>) -> result<list<redis-result>, error>;
  }

  /// The message payload.
  type payload = list<u8>;

  /// A parameter type for the general-purpose `execute` function.
  variant redis-parameter {
      int64(s64),
      binary(payload)
  }

  /// A return type for the general-purpose `execute` function.
  variant redis-result {
      nil,
      status(string),
      int64(s64),
      binary(payload)
  }
}