[swift-evolution] About the PermutationGenerator

[Dmitri Gribenko]

On Thu, Dec 31, 2015 at 2:01 PM, Susan Cheng via swift-evolution <
swift-evolution at swift.org> wrote:

> As I know SequenceType should have behaved as immutable structure and it
> provides method to get a mutable GeneratorType which generates value from
> start of sequence.


Sequences are not immutable.  A sequence is allowed to be consumed by
iterating over its generator.  If the type you have is a sequence, you can
only assume that you can access the elements only once.  For example, a
socket can be modeled as a sequence of bytes.  Once the bytes are consumed
from the corresponding generator, they are gone from the sequence.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
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