Provide abstraction for balanced grouping syntax.

diff --git a/v7/src/xml/turtle.scm b/v7/src/xml/turtle.scm
index 26f3279539e2a2b24836b1485e3af85bfb47cfd4..6eb4dde22adfb0b2d825b30dbd1e78d5f3736f0a 100644 (file)
--- a/v7/src/xml/turtle.scm
+++ b/v7/src/xml/turtle.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: turtle.scm,v 1.36 2007/12/09 04:42:03 cph Exp $
+$Id: turtle.scm,v 1.37 2007/12/09 04:50:54 cph Exp $
 
 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
     1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
@@ -718,7 +718,7 @@ USA.
                          indentation
                          inline-bnode
                          port))
-       (indentation (indent+ indentation)))
+         (indentation (indent+ indentation)))
       (let ((writer
             (and subject-inline?
                  (or (eq? (rdf-triple-predicate (caar groups)) rdf:type)
@@ -805,13 +805,11 @@ USA.
         (write-graph o indentation inline-bnode port))
        ((rdf-list->list o inline-bnode)
         => (lambda (os)
-             (write-string "(" port)
-             (let ((indentation (indent+ indentation)))
-               (for-each (lambda (o)
-                           (write-object o indentation inline-bnode port))
-                         os))
-             (write-indentation indentation port)
-             (write-string ")" port)))
+             (write-parens "(" ")" indentation port
+               (lambda (indentation)
+                 (for-each (lambda (o)
+                             (write-object o indentation inline-bnode port))
+                           os)))))
        ((inline-bnode o)
         => (lambda (ts)
              (write-inline-bnode (cdr ts) indentation inline-bnode port)))
@@ -819,11 +817,12 @@ USA.
         (error "Not an inline bnode:" o))))
 
 (define (write-inline-bnode ts indentation inline-bnode port)
-  (let ((groups (group-triples ts rdf-triple-predicate)))
-    (write-string "[" port)
-    (write-pgroups groups (indent+ indentation) inline-bnode port)
-    (write-indentation indentation port)
-    (write-string "]" port)))
+  (write-parens "[" "]" indentation port
+    (lambda (indentation)
+      (write-pgroups (group-triples ts rdf-triple-predicate)
+                    indentation
+                    inline-bnode
+                    port))))
 \f
 (define (write-subject s indentation inline-bnode port)
   (cond ((uri? s)
@@ -847,17 +846,15 @@ USA.
         (error "Unknown RDF subject:" s))))
 
 (define (write-graph graph indentation inline-bnode port)
-  (write-string "{" port)
-  (let ((indentation (indent+ indentation)))
-    (do ((groups (groups-to-write (rdf-graph-triples graph) inline-bnode)
-                (cdr groups)))
-       ((not (pair? groups)))
-      (write-indentation indentation port)
-      (write-group (car groups) indentation inline-bnode port)
-      (if (pair? (cdr groups))
-         (write-string "." port))))
-  (write-indentation indentation port)
-  (write-string "}" port))
+  (write-parens "{" "}" indentation port
+    (lambda (indentation)
+      (do ((groups (groups-to-write (rdf-graph-triples graph) inline-bnode)
+                  (cdr groups)))
+         ((not (pair? groups)))
+       (write-indentation indentation port)
+       (write-group (car groups) indentation inline-bnode port)
+       (if (pair? (cdr groups))
+           (write-string "." port))))))
 
 (define (write-predicate p port)
   (if (eq? p rdf:type)
@@ -977,6 +974,12 @@ USA.
 (define (write-symbol symbol port)
   (write-string (symbol-name symbol) port))
 
+(define (write-parens open close indentation port procedure)
+  (write-string open port)
+  (procedure (indent+ indentation))
+  (write-indentation indentation port)
+  (write-string close port))
+
 (define (write-indentation indentation port)
   (newline port)
   (let loop ((indentation indentation))