Make many into an iterative parser

1 files changed, 33 insertions, 0 deletions

diff --git a/quant.lisp b/quant.lisp
new file mode 100644
index 0000000..bdd0cfc
--- /dev/null
+++ b/quant.lisp
@@ -0,0 +1,33 @@
+(in-package #:monparser)
+
+(defparameter nothing
+  (new nil))
+
+(defun optional (p)
+  (one-of p nothing))
+
+(defun many (p &key all)
+  (lambda (input)
+    (let* ((result '())
+           (last-failure
+             (do ((r (funcall p input) (funcall p input))) ((failure-p r) r)
+               (when (parsing-p r)
+                 (setf input (parsing-left r))
+                 (when (parsing-tree r)
+                   (push (parsing-tree r) result))))))
+      (if (or (not result)
+              (and result all (has-data? (failure-place last-failure))))
+        (make-failure :place input :message (failure-message last-failure))
+        (make-parsing :tree (reverse result) :left input)))))
+
+; TODO: Need to be redone in a non-recursive way
+(defun repeat (p min &optional (max 0))
+  (if (> min 0)
+    (comp ((x p)
+           (xs (repeat p (1- min) (1- max))))
+      (cons x xs))
+    (if (> max 0)
+      (comp ((x (optional p))
+             (xs (repeat p 0 (if x (1- max) 0))))
+        (if x (cons x xs) x))
+      nothing)))