These are various mostly unorganized development notes related to things
that could later be done but haven't been done yet.

                      ------------------------------

Jon Ericson <Jonathan.L.Ericson@jpl.nasa.gov> sent the following two
patches for preliminary footnote support in Pod::Text and Pod::Man to
pod-people.  The code isn't quite the approach that I'd use, but it would
be a good starting point if the decision is ever made to implement
footnote support.

Here's his documentation followed by the patches.

=head1 Footnotes

Two POD elements are added to support footnotes:

=over 

=item * 

C<NE<lt>E<gt>> interior sequenceN<F was already taken.N<Nested
footnotes don't work correctly.  I don't think they should be
supported.>>

=item * 

C<=footnote> directiveN<1>

=back

=footnote 1

This method requires you to keep track of unique footnote IDs.  It
allows multiple paragraphs,N<0> 

  verbatim                                              paragraphs,

=begin text

and *format* specific paragraphs.

=end text

=begin html

<p>and <strong>format</strong> specific paragraphs.</p>

=end html

=footnote 0

I suppose this is neither here nor there, but I'm not a fan of
multi-sentence (much less multi-paragraph) footnotes.  If the
information is important, why not work it into the main text or put it
in the Appendix?  If it isn't important, why include it at all?

But some people seem to love them.  They put stories, jokes, code
examples, detailed arguments, disclaimers, etc. in footnotes.  As a
matter of principle, I wish they were disallowed in POD.
Unfortunately, it would then be impossible for Larry to write the next
I<Camel> in standard POD!N<You B<can> embed footnotes in the
multi-paragraph style, but I don't think it should be supported.>

=footnote

The most common use of the footnote is for short parenthetical
statements:

  =head1 Why I love Perl.N<www.perl.com>

  [Insert reasons here]

which gets formatted:

  Why I love Perl.[1]

  [Insert reasons here]

  ___
  1
      www.perl.com

For the vast majority of footnotes, this is all you need to know.  The
pod2X translators take care of the details for putting footnotes in X.
pod2latex uses C<\footnote>, pod2html uses <a> tags, pod2text puts
notes at the bottom of the document, etc.

There is a limitation to the interior sequence version of
footnotes---they can't contain pod paragraphs.N<*>  A general solution
for the problem would be to add a macro language to pod.  I thought
that it would be overkill.N<**>  Instead I added a footnote directive
that associates footnote text with a specific footnote mark.  For
instance if you wanted to make the HTML footnote different from the
text version you could do something like:

  =head1 Why I love Perl.N<12>

  [Insert reasons here]

  =footnote 12

  =for text

  www.perl.com

  =for html

  <a href="http://www.perl.com">The Perl web-site.</a>

  =footnote

First place a mark with the C<N> interior sequence.  Pod translators
use the contents of the mark as a footnote ID which must match
C</^[\d*]+$/>.  Sometime after the mark is placed, use the footnote
directive to start the footnote section for that footnote ID.
Footnote sections are ended with another footnote directive.  Note
that the footnote ID is only used to tie a specific footnote mark to
its text---the formatter is free to renumber (or re-mark) your
footnotes.

=footnote **

Not to mention beyond my abilities to do right. :)

=footnote *

LaTeX doesn't allow C<\verb> within footnotes, at least not without an
optional package.  (See
http://www.tex.ac.uk/cgi-bin/texfaq2html?keyword=footnote&question=143)

=footnote 42

This is an orphaned footnote.  It's just sort of stuck in here with a
footnote mark that doesn't go anywhere in the text.  Does anyone know
where, if anywhere, it makes sense to put these?

=cut

--- /src/podlators-1.08/lib/Pod/Text.pm	Sat Feb 10 06:50:23 2001
+++ /src/podlators/lib/Pod/Text.pm	Tue Mar 13 20:35:23 2001
@@ -330,6 +330,7 @@
     elsif ($command eq 'F') { return $self->seq_f ($_) }
     elsif ($command eq 'I') { return $self->seq_i ($_) }
     elsif ($command eq 'L') { return $self->seq_l ($_) }
+    elsif ($command eq 'N') { return $self->seq_n ($_) }
     else { carp "Unknown sequence $command<$_>" }
 }
 
@@ -461,6 +462,24 @@
     $self->verbatim ($_, $line);
 }
 
+sub cmd_footnote {
+    my $self = shift;
+    local $_ = shift;
+    s/\s+$//;
+    undef $$self{FOOTNOTE}, return unless length $_;
+    my $i = 0;
+    for my $note (@{$self->{NOTES}}) {
+	if ($note =~ /^[\d*]+$/) {
+	    if ($note eq $_) {
+		$$self{FOOTNOTE} = $i;
+		$self->{NOTES}[$i] = '';
+		return;
+	    }
+	}
+	$i++;
+    }
+    $$self{FOOTNOTE} = $i; # orphan footnote case
+}
 
 ############################################################################
 # Interior sequences
@@ -526,6 +545,35 @@
     $text;
 }
 
+sub seq_n {
+    my $self = shift;
+    push @{$self->{NOTES}}, shift;
+    return '[' . @{$self->{NOTES}} . ']';
+}
+
+sub notes {
+    my $self = shift;
+    undef $$self{FOOTNOTE};
+    if (defined $self->{NOTES}){
+	$self->output('_' x 3 . "\n"); # "___\n" doesn't work
+	for my $note (0..$#{$self->{NOTES}}) {
+	    $self->output ($note + 1 . "\n");
+	    for (split /\n\n/, $self->{NOTES}[$note]) {
+		if (/^\s/) {
+		    $_ = "$_\n";
+		} else {
+		    $_ = $self->reformat("$_\n");
+		}
+		$self->output ($_);
+	    }
+	}
+	undef $self->{NOTES};
+    }
+};
+
+sub end_input {
+    $_[0]->notes;
+}
 
 ############################################################################
 # List handling
@@ -615,7 +663,16 @@
 }
 
 # Output text to the output device.
-sub output { $_[1] =~ tr/\01/ /; print { $_[0]->output_handle } $_[1] }
+sub output {
+    my $self = shift;
+    local $_ = shift;
+    tr/\01/ /;
+    if (defined $$self{FOOTNOTE}) {
+	$self->{NOTES}[$$self{FOOTNOTE}] .= "$_\n";
+    } else {
+	print { $self->output_handle } $_;
+    }
+}
 
 
 ############################################################################


--- /src/podlators-1.08/lib/Pod/Man.pm	Sat Feb 10 06:50:22 2001
+++ /src/podlators/lib/Pod/Man.pm	Thu Mar 15 03:18:01 2001
@@ -614,6 +614,12 @@
     # Add an index entry to the list of ones waiting to be output.
     if ($command eq 'X') { push (@{ $$self{INDEX} }, $_); return '' }
 
+    if ($command eq 'N') {
+	push @{ $$self{NOTES} }, $_;
+        return bless \ ('\u\f(BS' . @{ $$self{NOTES} } . '\f(BE\d'),
+	  'Pod::Man::String';
+    }
+
     # Anything else is unknown.
     carp "Unknown sequence $command<$_>";
 }
@@ -785,6 +791,22 @@
     $self->output ($_);
 }
 
+sub cmd_footnote {
+    my $self = shift;
+    local $_ = shift;
+    s/\s+$//;
+    undef $$self{FOOTNOTE}, return unless length $_;
+    my $i = 0;
+    for my $note (@{$self->{NOTES}}) {
+	if ($note eq $_) {
+	    $$self{FOOTNOTE} = $i;
+	    $self->{NOTES}[$i] = '';
+	    return;
+	}
+	$i++;
+    }
+    $$self{FOOTNOTE} = $i; # orphan footnote case
+}
 
 ############################################################################
 # Link handling
@@ -1067,7 +1089,35 @@
 }
 
 # Output text to the output device.
-sub output { print { $_[0]->output_handle } $_[1] }
+sub output {
+    my $self = shift;
+    local $_ = shift;
+    if (defined $$self{FOOTNOTE}) {
+	$self->{NOTES}[$$self{FOOTNOTE}] .= $_;
+    } else {
+	print { $self->output_handle } $_;
+    }
+}
+
+sub notes {
+    my $self = shift;
+    undef $$self{FOOTNOTE};
+    if (defined $self->{NOTES}){
+	$self->makespace;
+	$self->output("___\n");
+	for my $note (0..$#{$self->{NOTES}}) {
+	    $self->makespace;
+	    $self->output ("\n" . $note + 1 . "\n");
+	    $self->makespace;
+	    $self->output ("$self->{NOTES}[$note]\n");
+	}
+	undef $self->{NOTES};
+    }
+};
+
+sub end_input {
+    $_[0]->notes;
+}
 
 # Given a command and a single argument that may or may not contain double
 # quotes, handle double-quote formatting for it.  If there are no double

                      ------------------------------

The following extra bits of *roff were in the original pod2man.  They're
not currently used, but I don't want to lose track of them in case they're
useful later.  They're for accents and special characters that Pod::Man
currently doesn't have E<> escapes for.

.if n \{\
.    ds ? ?
.    ds ! !
.    ds q
.\}
.if t \{\
.    ds ? \s-2c\h'-\w'c'u*7/10'\u\h'\*(#H'\zi\d\s+2\h'\w'c'u*8/10'
.    ds ! \s-2\(or\s+2\h'-\w'\(or'u'\v'-.8m'.\v'.8m'
.    ds q o\h'-\w'o'u*8/10'\s-4\v'.4m'\z\(*i\v'-.4m'\s+4\h'\w'o'u*8/10'
.\}
.ds v \\k:\h'-(\\n(.wu*9/10-\*(#H)'\v'-\*(#V'\*(#[\s-4v\s0\v'\*(#V'\h'|\\n:u'\*(
#]
.ds _ \\k:\h'-(\\n(.wu*9/10-\*(#H+(\*(#F*2/3))'\v'-.4m'\z\(hy\v'.4m'\h'|\\n:u'
.ds . \\k:\h'-(\\n(.wu*8/10)'\v'\*(#V*4/10'\z.\v'-\*(#V*4/10'\h'|\\n:u'
.ds 3 \*(#[\v'.2m'\s-2\&3\s0\v'-.2m'\*(#]
.ds oe o\h'-(\w'o'u*4/10)'e
.ds Oe O\h'-(\w'O'u*4/10)'E
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds v \h'-1'\o'\(aa\(ga'
.    ds _ \h'-1'^
.    ds . \h'-1'.
.    ds 3 3
.    ds oe oe
.    ds Oe OE
.\}

                      ------------------------------

Copyright 2001, 2003, 2016, 2018 Russ Allbery <rra@cpan.org>

This file is free software; you may redistribute it and/or modify it under
the same terms as Perl itself.

SPDX-License-Identifier: GPL-1.0-or-later OR Artistic-1.0-Perl
