handle %prefixkeyword command in title index.

make-index

@@ -17,15 +17,6 @@ sub uppercase($)
     return $letter;
 }
 
-sub get_first_letter($)
-{
-    my $string = shift;
-    $string =~ /([\w\d])/;
-    my $letter = $1;
-    $letter = "0-9" if ( $letter =~ /\d/ ); # group every numer into one category
-    return uppercase $letter;	
-}
-
 sub usage 
 { 
     print "usage: make-index source\n";
@@ -54,11 +45,35 @@ my $link;
 my $letter;
 my $ref;
 
+my @prefix = ();
+
+while( @data &&  ( $data[0] =~ /^\s*%prefix (.*)$/ ) )
+{
+    push @prefix, $1;
+    shift @data;
+}
+
+# Create the prefix rule
+my $prefix = '('. join ("|", @prefix) . ')';
+
+# Create the filter function
+sub filter($)
+{
+    my $string = shift;
+    $string =~ /^$prefix?[^\w]*([\w])/;
+    my $letter = $2;
+    $letter = "0-9" if ( $letter =~ /\d/ ); # group every numbers
+    
+    $string =~ s/^$prefix?\s?(.*)/$2, $1/ unless $prefix  eq "()";
+
+    return (uppercase $letter, $string);	
+}
+
+# Process data
 while( @data )
 {
     $item = shift @data;
-    unless( $item =~ /^\s*%/ ) # ignore a line starting with %
-    {
+    # entry goes on three lines
     chomp $item;
     $index = shift @data;
     chomp $index;
@@ -66,7 +81,7 @@ while( @data )
     chomp $link;
     
     # Get the first letter or number of the current item
-	$letter = get_first_letter $item;
+    ($letter, $item) = filter $item;
     
     # Create empty data index if needed
     $table{$letter} = {} unless exists $table{$letter};
@@ -77,7 +92,6 @@ while( @data )
     
     # Add the reference to the index
     push @{$table{$letter}{$item}}, $ref;
-    }
 }
 
 # Create the index formated file