+>> I certainly won't be fussy about how it gets implemented, I was just trying to think of the lightest weight most "wiki" solution. :-) -- Adam.
+
+>>> As a side note, the feature described above (having a form not to add a page but to expand it in a formated way) would be useful for other things when the content is short (timetracking, sub-todo list items, etc..) --[[hb]]
+
+# [[MarceloMagallon]]'s implementation
+
+I've been looking into this. I'd like to implement a "blogcomments"
+plugin. Looking at the code, I think the way to go is to have a
+formbuilder_setup hook that uses a different template instead of the
+standard editpage one. That template would not display the editcontent
+field. The problem that I'm running into is that I need to append the new
+content to the old one.
+
+-- [[MarceloMagallon]]
+
+> Anything I can do to help? --[[Joey]]
+
+>> Figured it out. Can you comment on the code below? Thanks. -- [[MarceloMagallon]]
+
+So, I have some code, included below. For some reason that I don't quite get it's not updating the wiki page after a submit. Maybe it's something silly on my side...
+
+What I ended up doing is write something like this to the page:
+
+ [[!blogcomment from="""Username""" timestamp="""12345""" subject="""Some text""" text="""the text of the comment"""]]
+
+Each comment is processed to something like this:
+
+ <div>
+ <dl>
+ <dt>From</dt><dd>Username</dd>
+ <dt>Date</dt><dd>Date (needs fixing)</dd>
+ <dt>Subject</dt><dd>Subject text</dd>
+ </dl>
+
+ <p>Text of the comment...</p>
+ </div>
+
+. In this way the comments can be styled using CSS.
+
+-- [[MarceloMagallon]]
+
+## Code
+
+ #!/usr/bin/perl
+ package IkiWiki::Plugin::comments;
+
+ use warnings;
+ use strict;
+ use IkiWiki '1.02';
+
+ sub import {
+ hook(type => "formbuilder_setup", id => "comments",
+ call => \&formbuilder_setup);
+ hook(type => "preprocess", id => "blogcomment",
+ call => \&preprocess);
+ }
+
+ sub formbuilder_setup (@) {
+ my %params=@_;
+ my $cgi = $params{cgi};
+ my $form = $params{form};
+ my $session = $params{session};
+
+ my ($page)=$form->field('page');
+ $page=IkiWiki::titlepage(IkiWiki::possibly_foolish_untaint($page));
+
+ # XXX: This needs something to make it blog specific
+ unless ($page =~ m{/discussion$} &&
+ $cgi->param('do') eq 'edit' &&
+ ! exists $form->{title})
+ {
+ return;
+ }
+
+ if (! $form->submitted)
+ {
+ $form->template(IkiWiki::template_file("makeblogcomment.tmpl"));
+ $form->field(name => "blogcomment", type => "textarea", rows => 20,
+ cols => 80);
+ return;
+ }
+
+ my $content="";
+ if (exists $pagesources{$page}) {
+ $content=readfile(srcfile($pagesources{$page}));
+ $content.="\n\n";
+ }
+ my $name=defined $session->param('name') ?
+ $session->param('name') : gettext('Anonymous');
+ my $timestamp=time;
+ my $subject=defined $cgi->param('comments') ?
+ $cgi->param('comments') : '';
+ my $comment=$cgi->param('blogcomment');
+
+ $content.=qq{[[!blogcomment from="""$name""" timestamp="""$timestamp""" subject="""$subject""" text="""$comment"""]]\n\n};
+ $content=~s/\n/\r\n/g;
+ $form->field(name => "editcontent", value => $content, force => 1);
+ }
+
+ sub preprocess (@) {
+ my %params=@_;
+
+ my ($text, $date, $from, $subject, $r);
+
+ $text=IkiWiki::preprocess($params{page}, $params{destpage},
+ IkiWiki::filter($params{page}, $params{text}));
+ $from=exists $params{from} ? $params{from} : gettext("Anonymous");
+ $date=localtime($params{timestamp}) if exists $params{timestamp};
+ $subject=$params{subject} if exists $params{subject};
+
+ $r = qq{<div class="blogcomment"><dl>\n};
+ $r .= '<dt>' . gettext("From") . "</dt><dd>$from</dd>\n" if defined $from;
+ $r .= '<dt>' . gettext("Date") . "</dt><dd>$date</dd>\n" if defined $date;
+ $r .= '<dt>' . gettext("Subject") . "</dt><dd>$subject</dd>\n"
+ if defined $subject;
+ $r .= "</dl>\n" . $text . "</div>\n";
+
+ return $r;
+ }
+
+ 1;
+
+# [[smcv]]'s implementation
+
+I've started a smcvpostcomment plugin (to be renamed to postcomment if people like it, but I'm namespacing it while it's still experimental) which I think more closely resembles what Joey was after. The code is cargo-culted from a mixture of editpage and inline's "make a blog post" support - it has to use a lot of semi-internal IkiWiki:: functions (both of those plugins do too). It doesn't fully work yet, but I'll try to get it into a state where it basically works and can be published in the next week or two.
+
+My approach is:
+
+* Comments are intended to be immutable after posting (so, only editable by direct committers), so they go on internal pages (*._comment); these internal pages are checked in to the RCS (although later I might make this optional)
+
+* ?do=smcvpostcomment (in the CGI script) gives a form that lets logged-in users (later, optionally also anonymous users) create a new comment
+
+* \[[!smcvpostcomment]] just inserts a "Post comment" button into the current page, which goes to ?do=smcvpostcomment - it's intended to be used in conjunction with an \[[!inline]] that will display the comments
+
+* The title (subject line), author and authorurl are set with \[[!meta]] directives, just like the way aggregate does it (which means I'll probably have to disallow the use of those \[[!meta]] directives in the body of the comment, to avoid spoofing - obviously, spoofing can be detected by looking at RecentChanges or gitweb, but the expectation for blog-style comments is that the metadata seen in the comment can be trusted)
+
+* The initial plan is to have comments hard-coded to be in Markdown, with further directives not allowed - I'll relax this when I've worked out what ought to be allowed!
+
+I've also updated Marcelo's code (above) to current ikiwiki, and moved it to a "marceloblogcomment" namespace - it's in the "marcelocomments" branch of my repository (see <http://git.debian.org/?p=users/smcv/ikiwiki.git;a=log;h=refs/heads/marcelocomments>). I had to reconstitute the .tmpl file, which Marcelo didn't post here.
+
+--[[smcv]]
+
+OK, the postcomment branch in my repository contains an implementation. What
+do you think so far? Known issues include:
+
+* The combination of RSS/Atom links and the "post new comment..." button is
+ ugly - I need a way to integrate the "new comment" button into the feed links
+ somehow, like the way inline embeds its own "new blog post..." feature
+ (I don't think the current way really scales, though)
+
+* There are some tweakables (whether to commit comments into the VCS, whether
+ wikilinks are allowed, whether directives are allowed) that are theoretically
+ configurable, but are currently hard-coded
+
+* The wikilink/directive disarming doesn't work unless you have
+ prefixdirectives set (which I just realised)
+
+* \[[!smcvpostcomment]] now displays the comments too, by invoking \[[!inline]]
+ with suitable parameters - but it does so in a very ugly way
+
+* Start-tags in a comment with no corresponding end-tag break page formatting
+ (unless htmltidy is enabled - inline and aggregate have the same problem)
+
+* There is no access control, so anonymous users can always comment, and so
+ can all logged-in users. Perhaps we need to extend canedit() to support
+ different types of edit? Or perhaps I should ignore canedit() and make the
+ access control configurable via a parameter to \[[!smcvpostcomment]]?
+ I'd like to be able to let anonymous (or at least non-admin) users comment
+ on existing pages, but not edit or create pages (but perhaps I'm being too
+ un-wikiish).
+
+--[[smcv]]
+
+I've updated smcvpostcomment and publicised it as [[plugins/contrib/comments]]. --[[smcv]]
+
+> While there is still room for improvement and entirely other approaches,
+> I am calling this done since smcv's comments plugin is ready. --[[Joey]]