1 files changed, 51 insertions, 0 deletions
diff --git a/base.lisp b/base.lisp
new file mode 100644
index 0000000..8206322
--- /dev/null
+++ b/base.lisp
@@ -0,0 +1,51 @@
+(in-package #:monparser)
+
+(defstruct parsing
+  tree
+  left
+  limit)
+
+(defstruct failure
+  place
+  message)
+
+(defun lazy-parsing-p (r)
+  (or (functionp r)
+      (parsing-p r)))
+
+(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))))
+
+(defun bind (p f &key (greedy t))
+  (lambda (input &key limit lazy)
+    (let (r)
+      (if greedy
+        (setf r (funcall p input :limit limit))
+        (let ((next-parser (funcall f nil input))
+              (limit -1))
+          (do ((sweep-input input (advance sweep-input)))
+            ((or (not (has-data? sweep-input))
+                 (> 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 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))))