From 23ae7026a8a798ea465f3ba18aca85e4f3a2f715 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Thu, 16 May 2002 06:40:56 +0000
Subject: [PATCH] Generate "hanging comma" clauses in the index

---
 doc/genps.pl | 40 ++++++++++++++++++++++++++++++++++------
 doc/head.ps  | 14 ++++++++++++++
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/doc/genps.pl b/doc/genps.pl
index b4e230a..b079ac5 100755
--- a/doc/genps.pl
+++ b/doc/genps.pl
@@ -29,7 +29,7 @@ use Fcntl;
 	   tocpnz => 24,	# Width of TOC page number only zone
 	   tocdots => 8,	# Spacing between TOC dots
 	   idxspace => 24,	# Minimum space between index title and pg#
-	   idxindent => 32,	# How much to indent a subindex entry
+	   idxindent => 24,	# How much to indent a subindex entry
 	   idxgutter => 24,	# Space between index columns
 	   idxcolumns => 2,	# Number of index columns
 	   );
@@ -173,7 +173,7 @@ while ( defined($line = <PARAS>) ) {
 	$ixterms{$ixentry} = [split(/\037/, $data)];
 	# Look for commas.  This is easier done on the string
 	# representation, so do it now.
-	if ( $line =~ /^(.*\,)\037sp\037/ ) {
+	if ( $data =~ /^(.*\,)\037sp\037/ ) {
 	    $ixprefix = $1;
 	    $ixhasprefix{$ixentry} = $ixprefix;
 	    if ( !$ixprefixes{$ixprefix} ) {
@@ -724,7 +724,9 @@ sub ps_break_pages($$) {
     my $nobreakregexp = "^(chap|appn|head|subh|toc.|idx.)\$";
     # Paragraph types which are heading (meaning they should not be broken
     # immediately after)
-    my $headingregexp = "^(chap|appn|head|subh)\$";
+    my $nobreakafter = "^(chap|appn|head|subh)\$";
+    # Paragraph types which should never be broken *before*
+    my $nobreakbefore = "^idx[1-9]\$";
     # Paragraph types which are set in columnar format
     my $columnregexp = "^idx.\$";
 
@@ -771,7 +773,8 @@ sub ps_break_pages($$) {
 		} elsif ( $$linfo[1] & 1 ) {
 		    # Sole line or start of paragraph.  Break unless
 		    # the previous line was part of a heading.
-		    $broken = 1 if ( $$pinfo[0] !~ /$headingregexp/o );
+		    $broken = 1 if ( $$pinfo[0] !~ /$nobreakafter/o &&
+				     $$linfo[0] !~ /$nobreakbefore/o );
 		} else {
 		    # Middle of paragraph.  Break unless we're in a
 		    # no-break paragraph, or the previous line would
@@ -839,7 +842,32 @@ $startofindex = scalar(@pslines);
 foreach $k ( @ixentries ) {
     my $n,$i;
     my $ixptype = 'idx0';
-    my @ixpara = mkparaarray('idx0',@{$ixterms{$k}});
+    my $prefix = $ixhasprefix{$k};
+    my @ixpara = mkparaarray($ixptype,@{$ixterms{$k}});
+    my $commapos = undef;
+
+    if ( defined($prefix) && $ixprefixes{$prefix} > 1 ) {
+	# This entry has a "hanging comma"
+	for ( $i = 0 ; $i < scalar(@ixpara)-1 ; $i++ ) {
+	    if ( substr($ixpara[$i]->[1],-1,1) eq ',' &&
+		 $ixpara[$i+1]->[1] eq ' ' ) {
+		$commapos = $i;
+		last;
+	    }
+	}
+    }
+    if ( defined($commapos) ) {
+	if ( $ixcommafirst{$k} ) {
+	    # This is the first entry; generate the
+	    # "hanging comma" entry
+	    push(@ixparas, [splice(@ixpara,0,$commapos+1),[-6,undef]]);
+	    push(@ixptypes, $ixptype);
+	    shift(@ixpara);	# Remove space
+	} else {
+	    splice(@ixpara,0,$commapos+2);
+	}
+	$ixptype = 'idx1';
+    }
 
     push(@ixpara, [-6,undef]);	# Left/right marker
     $i = 1;  $n = scalar(@{$ps_index_pages{$k}});
@@ -944,7 +972,7 @@ foreach $fset ( @AllFonts ) {
     print '/', $fset->{name}, ' [', join(' ',@zfonts), "] def\n";
 }
 
-# Emit the result as PostScript.  This is *NOT* correct code yet!
+# Emit the canned PostScript prologue
 open(PSHEAD, "< head.ps");
 while ( defined($line = <PSHEAD>) ) {
     print $line;
diff --git a/doc/head.ps b/doc/head.ps
index e85ffcc..4cfc0ea 100644
--- a/doc/head.ps
+++ b/doc/head.ps
@@ -327,6 +327,20 @@
 /idx01 {idx03} def
 /idx02 {idx03} def
 
+/idx13 {
+  2 dict begin
+    indexcolumn mul lmarg add idxindent add
+    /x exch def /y exch def x y moveto
+    exch bfont showstream
+    dup bfont streamwidth
+    x indexcolwid idxindent sub add exch sub exch pop y moveto
+    bfont showstream
+  end
+} def
+/idx10 {idx13} def
+/idx11 {idx13} def
+/idx12 {idx13} def
+
 %
 % Page numbers
 %
-- 
2.7.4