diff options
Diffstat (limited to 'base.lisp')
-rw-r--r-- | base.lisp | 49 |
1 files changed, 25 insertions, 24 deletions
@@ -15,37 +15,38 @@ (defun new (tree) (lambda (input &key limit lazy) - (declare (ignore lazy)) - (if (and limit (> limit 0)) - (make-failure :place input - :message (format nil "Didn't reach expected limit: ~a." limit)) - (make-parsing :tree tree :left input)))) + (declare (ignore limit lazy)) + (make-parsing :tree tree :left input))) -(defun bind (p f &key (greedy t)) +(defun bind (parser f &key (greedy t)) (lambda (input &key limit lazy) (let (r) (if greedy - (setf r (funcall p input :limit limit)) + (setf r (funcall parser input :limit limit)) (let ((next-parser (funcall f nil input)) - (limit -1)) + (inner-limit -1)) (do ((sweep-input input (advance sweep-input))) ((or (not (has-data? sweep-input)) - (> limit -1)) nil) + (and limit (> (cursor-distance sweep-input input) limit)) + (> inner-limit -1)) nil) (when (lazy-parsing-p (funcall next-parser sweep-input :lazy t)) - (setf limit (cursor-distance sweep-input input)))) - (if (< limit 0) + (setf inner-limit (cursor-distance sweep-input input)) + (when limit (decf limit inner-limit)))) + (if (< inner-limit 0) (setf r (make-failure :place input :message "Reached end of input while sweeping.")) - (setf r (funcall p input :limit limit))))) - (if (parsing-p r) - (if lazy - (lambda (ignored-input &key lazy limit) - (declare (ignore ignored-input limit)) - (funcall (funcall f (parsing-tree r) input) - (parsing-left r) - :lazy lazy - :limit (if greedy (parsing-limit r)))) - (funcall (funcall f (parsing-tree r) input) - (parsing-left r) - :limit (if greedy (parsing-limit r)))) - r)))) + (setf r (funcall parser input :limit inner-limit))))) + (cond ((parsing-p r) + (if lazy + (lambda (ignored-input &key lazy limit) + (declare (ignore ignored-input)) + (funcall (funcall f (parsing-tree r) input) + (parsing-left r) + :lazy lazy + :limit (if greedy (parsing-limit r) limit))) + (funcall (funcall f (parsing-tree r) input) + (parsing-left r) + :limit (if greedy (parsing-limit r) limit)))) + ((failure-p r) + r) + (t (error (format nil "Invalid return value: ~a" r))))))) |