| package main | |
| import "sync" | |
| type LazyPrimes struct { | |
| once sync.Once // Guards the primes slice. | |
| primes []int | |
| } | |
| func (p *LazyPrimes) init() { | |
| // Populate p.primes with prime numbers. | |
| } | |
| func (p *LazyPrimes) Primes() []int { | |
| p.once.Do(p.init) | |
| return p.primes | |
| } |