Sidekick block asset: show first line only;

--- a/src/Pure/library.scala	Wed Nov 10 20:21:55 2010 +0100
+++ b/src/Pure/library.scala	Wed Nov 10 20:43:22 2010 +0100
@@ -82,6 +82,13 @@
       }
   }
 
+  def first_line(source: CharSequence): String =
+  {
+    val lines = chunks(source)
+    if (lines.hasNext) lines.next.toString
+    else ""
+  }
+
 
   /* simple dialogs */
 

--- a/src/Tools/jEdit/src/jedit/isabelle_sidekick.scala	Wed Nov 10 20:21:55 2010 +0100
+++ b/src/Tools/jEdit/src/jedit/isabelle_sidekick.scala	Wed Nov 10 20:43:22 2010 +0100
@@ -121,7 +121,7 @@
         case Structure.Block(name, body) =>
           val node =
             new DefaultMutableTreeNode(
-              new Isabelle_Sidekick.Asset(name, offset, offset + entry.length))
+              new Isabelle_Sidekick.Asset(Library.first_line(name), offset, offset + entry.length))
           (offset /: body)((i, e) =>
             {
               make_tree(i, e) foreach (nd => node.add(nd))