?next ( gen -- val/f end? )
Generators

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Vocabulary
generators

Inputs

gen	a generator

Outputs

val/f	an object or f
end?	a boolean

Word description
A safe version of next. Also returns a boolean indicating whether the end of the generator was reached.

Definition

USING: kernel ;

IN: generators

: ?next ( gen -- val/f end? )
    [ next f ] [ drop f t ] catch-stop-generator ;