From 7efd05778cddec0293e0d48199f3aeee2aad6178 Mon Sep 17 00:00:00 2001
From: Ludovic Courtès
Date: Fri, 18 Jan 2008 12:36:59 +0100
Subject: Add SILex, for simplicity.

---
 src/guile/silex/noeps.scm | 95 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 src/guile/silex/noeps.scm

(limited to 'src/guile/silex/noeps.scm')

diff --git a/src/guile/silex/noeps.scm b/src/guile/silex/noeps.scm
new file mode 100644
index 0000000..fcca605
--- /dev/null
+++ b/src/guile/silex/noeps.scm
@@ -0,0 +1,95 @@
+; SILex - Scheme Implementation of Lex
+; Copyright (C) 2001  Danny Dube'
+; 
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation; either version 2
+; of the License, or (at your option) any later version.
+; 
+; This program is distributed in the hope that it will be useful,
+; but WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+; GNU General Public License for more details.
+; 
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, write to the Free Software
+; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+; Fonction "merge" qui elimine les repetitions
+(define noeps-merge-1
+  (lambda (l1 l2)
+    (cond ((null? l1)
+	   l2)
+	  ((null? l2)
+	   l1)
+	  (else
+	   (let ((t1 (car l1))
+		 (t2 (car l2)))
+	     (cond ((< t1 t2)
+		    (cons t1 (noeps-merge-1 (cdr l1) l2)))
+		   ((= t1 t2)
+		    (cons t1 (noeps-merge-1 (cdr l1) (cdr l2))))
+		   (else
+		    (cons t2 (noeps-merge-1 l1 (cdr l2))))))))))
+
+; Fabrication des voisinages externes
+(define noeps-mkvois
+  (lambda (trans-v)
+    (let* ((nbnodes (vector-length trans-v))
+	   (arcs (make-vector nbnodes '())))
+      (let loop1 ((n 0))
+	(if (< n nbnodes)
+	    (begin
+	      (let loop2 ((trans (vector-ref trans-v n)) (ends '()))
+		(if (null? trans)
+		    (vector-set! arcs n ends)
+		    (let* ((tran (car trans))
+			   (class (car tran))
+			   (end (cdr tran)))
+		      (loop2 (cdr trans) (if (eq? class 'eps)
+					     (noeps-merge-1 ends (list end))
+					     ends)))))
+	      (loop1 (+ n 1)))))
+      arcs)))
+
+; Fabrication des valeurs initiales
+(define noeps-mkinit
+  (lambda (trans-v)
+    (let* ((nbnodes (vector-length trans-v))
+	   (init (make-vector nbnodes)))
+      (let loop ((n 0))
+	(if (< n nbnodes)
+	    (begin
+	      (vector-set! init n (list n))
+	      (loop (+ n 1)))))
+      init)))
+
+; Traduction d'une liste d'arcs
+(define noeps-trad-arcs
+  (lambda (trans dict)
+    (let loop ((trans trans))
+      (if (null? trans)
+	  '()
+	  (let* ((tran (car trans))
+		 (class (car tran))
+		 (end (cdr tran)))
+	    (if (eq? class 'eps)
+		(loop (cdr trans))
+		(let* ((new-end (vector-ref dict end))
+		       (new-tran (cons class new-end)))
+		  (cons new-tran (loop (cdr trans))))))))))
+
+; Elimination des transitions eps
+(define noeps
+  (lambda (nl-start no-nl-start arcs acc)
+    (let* ((digraph-arcs (noeps-mkvois arcs))
+	   (digraph-init (noeps-mkinit arcs))
+	   (dict (digraph digraph-arcs digraph-init noeps-merge-1))
+	   (new-nl-start (vector-ref dict nl-start))
+	   (new-no-nl-start (vector-ref dict no-nl-start)))
+      (let loop ((i (- (vector-length arcs) 1)))
+	(if (>= i 0)
+	    (begin
+	      (vector-set! arcs i (noeps-trad-arcs (vector-ref arcs i) dict))
+	      (loop (- i 1)))))
+      (list new-nl-start new-no-nl-start arcs acc))))
-- 
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