Loop structures: Difference between revisions

==SETL4==

<lang setl4>

define('prime(n)set.this') :(prime.end)

* Tests if _n_ is a prime integer.

prime

n = integer(n) +n

eq(n,2) :s(return)

even(n) :s(freturn)

exists(new('iter 3 ' square.root(n) ' 2'), 'multiple(n,this)') :s(freturn)f(return)

prime.end

define('primes(n)set.this') :(primes.end)

* Returns set of primes less than _n_.

primes

primes = filter(new('iter 2 ' (n - 1)),'prime(this)') :(return)

primes = new('set')

iter = new('iter 2 ' (n - 1))

loop(iter)

primes.loop

this = next(iter) :f(return)

prime(this) add(primes,this) :(primes.loop)

primes.end

</lang>