diff options
Diffstat (limited to 'gtwiwtg.lisp')
| -rw-r--r-- | gtwiwtg.lisp | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/gtwiwtg.lisp b/gtwiwtg.lisp index 5394224..42e7731 100644 --- a/gtwiwtg.lisp +++ b/gtwiwtg.lisp @@ -148,6 +148,15 @@ (stop (slot-value gen 'source-generator))) +(a-generator-class resumable-generator! () + (wrapped (error "Resumable generators must wrap another generator"))) + +(defmethod next ((gen resumable-generator!)) + (next (slot-value gen 'wrapped))) + +(defmethod has-next-p ((gen resumable-generator!)) + (gtwiwtg::has-next-p (slot-value gen 'wrapped))) + ;;; CONSTRUCTORS (defun range (&key (from 0) to (by 1) inclusive) @@ -360,6 +369,31 @@ The last generated value of the returned generator will be NIL. ;;; MODIFIERS and COMBINATORS +(defun make-resumable! (gen) + "Makes a generator resumable. + +> (defvar *foobar* (make-resumable! (range))) +*FOOBAR* + +> (take 10 *foobar*) +(0 1 2 3 4 5 6 7 8 9) + +> (setf *foobar* (resume! *foobar*)) + +> (take 10 *foobar*) +(10 11 12 13 14 15 16 17 18 19) +" + (sully-when-clean (list gen)) + (make-instance 'resumable-generator! :wrapped gen)) + +(defun can-be-resumed-p (gen) + (and (typep gen 'resumable-generator!) + (stopped-p gen))) + +(defun resume! (resumable) + (assert (can-be-resumed-p resumable)) + (make-instance 'resumable-generator! :wrapped (slot-value resumable 'wrapped))) + (defun map! (map-fn gen &rest gens) "Maps a function over a number of generators, returning a generator that produces values that result from calling MAP-FN on those |