diff options
| -rw-r--r-- | gtwiwtg.lisp | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/gtwiwtg.lisp b/gtwiwtg.lisp index 896a733..46f8752 100644 --- a/gtwiwtg.lisp +++ b/gtwiwtg.lisp @@ -2,7 +2,10 @@ (in-package :gtwiwtg) (defclass generator! () - ((state + ((dirty-p + :accessor dirty-p + :initform nil) + (state :accessor gen-state :initarg :state :initform (error "no state")) @@ -20,7 +23,8 @@ (defmethod next ((gen generator!)) (assert (has-next-p gen)) - (with-slots (state next-fn) gen + (with-slots (state next-fn dirty-p) gen + (setf dirty-p t) (multiple-value-bind (val new-state) (funcall next-fn state) (setf state new-state) val))) @@ -80,6 +84,13 @@ the values passed as ARGS looped forever." (defun all-different (things) (= (length things) (length (remove-duplicates things)))) + +(defun all-clean (gens) + (every (complement #'dirty-p) gens)) + +(defun all-good (gens) + (and (all-clean gens) (all-different gens))) + ;;; MODIFIERS and COMBINATORS (defmethod yield-to! (gen1 gen2) @@ -123,7 +134,7 @@ generators. THIS FUNCTION MODIFIES AND RETURNS ITS FIRST GENERATOR ARGUMENT. Also, all of the generators must be different from one another. If any compare EQL then an error is signaled." - (assert (all-different (list* gen gens))) + (assert (all-good (list* gen gens))) (let ((orig-fns (mapcar #'next-fn (cons gen gens))) (orig-preds (mapcar #'next-p-fn (cons gen gens)))) (setf (gen-state gen) (mapcar #'gen-state (cons gen gens)) @@ -151,6 +162,7 @@ compare EQL then an error is signaled." when applied to PRED. THIS FUNCTION MODIFIES AND RETURNS ITS GENERATOR ARGUMENT." + (assert (not (dirty-p gen))) (let* ((orig-fn (next-fn gen)) (orig-p-fn (next-p-fn gen)) (last-good nil) @@ -186,6 +198,7 @@ equivalent to (FUNCALL #'CONCAT! (MAP! FN GEN)) That is it generates each element of (FN X) for each X in GEN. BIND! MODIFIES AND RETURNS ITS GENERATOR ARGUMENT." + (assert (not (dirty-p gen))) (let ((orig-fn (next-fn gen)) (orig-p (next-p-fn gen)) (orig-state (gen-state gen))) @@ -213,7 +226,7 @@ Each of the arguments to CONCAT! must be different. If any compare EQL, an error will be signalled. CONCAT! MODIFIES AND RETURNS ITS FIRST ARGUMENT." - (assert (all-different (list* gen gens))) + (assert (all-good (list* gen gens))) (bind! #'identity (seq (list* gen gens)))) (defun zip! (gen &rest gens) |