// Package priorityq provides generic implementations of various concurrent,
// prioritized queues.
//
// # Behavior
//
// All types of queues in this module act similarly to buffered Go channels.
//
//   - They are bounded to a fixed capacity, set at construction.
//   - Closing and sending to an already-closed queue causes a panic.
//   - Receivers can continue getting items after closure, and can use a final
//     bool to determine when there are none remaining.
//   - They are safe for multiple concurrent senders and receivers.
//
// # Implementation
//
// All data structures in this module use [generics], introduced in Go 1.18.
//
// All of the concurrent data structures in this package use a [sync.Mutex]
// and a few [sync.Cond] variables.
//
// [generics]: https://go.dev/blog/intro-generics
package priorityq

import (
	"fmt"
)

// ErrEmpty means that an operation failed because the queue was empty.
var ErrEmpty error

// ErrFull means that an operation failed because the queue was full.
var ErrFull error

// ErrClosed means that an operation failed because the queue was closed.
var ErrClosed error

func init() {
	ErrEmpty = fmt.Errorf("queue is empty")
	ErrFull = fmt.Errorf("queue is full")
	ErrClosed = fmt.Errorf("queue is closed")
}