cl: Tidy up parser slightly.

Most of the other implementations don't have separate cases for end-of-
input and not-open-paren; so don't penalize Lisp because I decided to
make the parser more extendable.

diff --git a/cl-fringe.lisp b/cl-fringe.lisp
index 3716f3b230d4a8a7a1f934a64ce6d74f710f8c39..a2ddf85509d9352ebc69d3a644b17d807440502a 100644 (file)
--- a/cl-fringe.lisp
+++ b/cl-fringe.lisp
@@ -63,9 +63,7 @@ (defun parse-tree (string)
 
   (let ((len (length string)))
     (labels ((parse (i)
 
   (let ((len (length string)))
     (labels ((parse (i)

-              (cond ((>= i len)
-                     (values nil i))
-                    ((char= (char string i) #\()
+              (cond ((and (< i len) (char= (char string i) #\())

                      (multiple-value-bind (left i) (parse (1+ i))
                        (unless (< i len) (error "no data"))
                        (let ((data (char string i)))
                      (multiple-value-bind (left i) (parse (1+ i))
                        (unless (< i len) (error "no data"))
                        (let ((data (char string i)))