--- cvs-head/lib/WAIT/InvertedIndex.pm	2000/04/28 15:40:52	10
+++ branches/CPAN/lib/WAIT/InvertedIndex.pm	2000/04/28 15:42:44	13
@@ -1,5 +1,5 @@
-#                              -*- Mode: Perl -*- 
-# InvertedIndex.pm -- 
+#                              -*- Mode: Cperl -*- 
+# InvertedIndex.pm --
 # ITIID           : $ITI$ $Header $__Header$
 # Author          : Ulrich Pfeifer
 # Created On      : Thu Aug  8 13:05:10 1996
@@ -7,9 +7,9 @@
 # Last Modified On: Sun Nov 22 18:44:42 1998
 # Language        : CPerl
 # Status          : Unknown, Use with caution!
-# 
+#
 # Copyright (c) 1996-1997, Ulrich Pfeifer
-# 
+#
 
 package WAIT::InvertedIndex;
 use strict;
@@ -63,9 +63,12 @@
 sub _xfiltergen {
   my $filter = pop @_;
 
-  if ($filter eq 'stop') {      # avoid the slow stopword elimination
-    return _xfiltergen(@_);            # it's cheaper to look them up afterwards
-  }
+# Oops, we cannot overrule the user's choice. Other filters may kill
+# stopwords, such as isotr clobbers "isn't" to "isnt".
+
+#  if ($filter eq 'stop') {      # avoid the slow stopword elimination
+#    return _xfiltergen(@_);            # it's cheaper to look them up afterwards
+#  }
   if (@_) {
     if ($filter =~ /^split(\d*)/) {
       if ($1) {
@@ -148,7 +151,7 @@
   my $self  = shift;
   my $key   = shift;
   my %occ;
-  
+
   defined $self->{db} or $self->open;
   grep $occ{$_}++, &{$self->{func}}(@_);
   my ($word, $noc);
@@ -160,7 +163,7 @@
     } else {
       $self->{cdict}->{$O,$word} = 1;
       $self->{cache}->{$word}  = pack 'w2', $key, $noc;
-    } 
+    }
     $self->{cached}++;
   }
   $self->sync if $self->{cached} > 100_000;
@@ -277,6 +280,13 @@
   &{$self->{func}}(@_);
 }
 
+sub keys {
+  my $self  = shift;
+
+  defined $self->{db} or $self->open;
+  keys %{$self->{db}};
+}
+
 sub search_prefix {
   my $self  = shift;
 
@@ -298,7 +308,7 @@
   for (keys %occ) {
     if (defined $self->{db}->{$_}) {
       my %post = unpack 'w*', $self->{db}->{$_};
-      my $idf = log($self->{records}/$self->{db}->{$O,$_});
+      my $idf = log($self->{records}/($self->{db}->{$O,$_} || 1));
       my $did;
       for $did (keys %post) {
         $score{$did} = 0 unless defined $score{$did}; # perl -w 
@@ -314,7 +324,7 @@
   my $self = shift;
 
   if ($self->{mode} & O_RDWR) {
-    print STDERR "\aFlushing $self->{cached} postings\n";
+    print STDERR "Flushing $self->{cached} postings\n";
     while (my($key, $value) = each %{$self->{cache}}) {
       $self->{db}->{$key} .= $value;
       #delete $self->{cache}->{$key};