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+## Why internal pages? (unresolved)
+
+Comments are saved as internal pages, so they can never be edited through the CGI,
+only by direct committers.
+
+> So, why do it this way, instead of using regular wiki pages in a
+> namespace, such as `$page/comments/*`? Then you could use [[plugins/lockedit]] to
+> limit editing of comments in more powerful ways. --[[Joey]]
+
+>> Er... I suppose so. I'd assumed that these pages ought to only exist as inlines
+>> rather than as individual pages (same reasoning as aggregated posts), though.
+>>
+>> lockedit is actually somewhat insufficient, since `check_canedit()`
+>> doesn't distinguish between creation and editing; I'd have to continue to use
+>> some sort of odd hack to allow creation but not editing.
+>>
+>> I also can't think of any circumstance where you'd want a user other than
+>> admins (~= git committers) and possibly the commenter (who we can't check for
+>> at the moment anyway, I don't think?) to be able to edit comments - I think
+>> user expectations for something that looks like ordinary blog comments are
+>> likely to include "others can't put words into my mouth".
+>>
+>> My other objection to using a namespace is that I'm not particularly happy about
+>> plugins consuming arbitrary pieces of the wiki namespace - /discussion is bad
+>> enough already. Indeed, this very page would accidentally get matched by rules
+>> aiming to control comment-posting... :-) --[[smcv]]
+
+>>> Thinking about it, perhaps one way to address this would be to have the suffix
+>>> (e.g. whether commenting on Sandbox creates sandbox/comment1 or sandbox/c1 or
+>>> what) be configurable by the wiki admin, in the same way that recentchanges has
+>>> recentchangespage => 'recentchanges'? I'd like to see fewer hard-coded page
+>>> names in general, really - it seems odd to me that shortcuts and smileys
+>>> hard-code the name of the page to look at. Perhaps I could add
+>>> discussionpage => 'discussion' too? --[[smcv]]
+
+>>> (I've now implemented this in my branch. --[[smcv]])
+
+>> The best reason to keep the pages internal seems to me to be that you
+>> don't want the overhead of every comment spawning its own wiki page. --[[Joey]]
+
+## Formats (resolved)
+
+The plugin now allows multiple comment formats while still using internal
+pages; each comment is saved as a page containing one `\[[!comment]]` directive,
+which has a superset of the functionality of [[ikiwiki/directives/format]].
+
+## Access control (unresolved?)
+
+By the way, I think that who can post comments should be controllable by
+the existing plugins opendiscussion, anonok, signinedit, and lockedit. Allowing
+posting comments w/o any login, while a nice capability, can lead to
+spam problems. So, use `check_canedit` as at least a first-level check?
+--[[Joey]]
+
+> This plugin already uses `check_canedit`, but that function doesn't have a concept
+> of different actions. The hack I use is that when a user comments on, say, sandbox,
+> I call `check_canedit` for the pseudo-page "sandbox[postcomment]". The
+> special `postcomment(glob)` [[ikiwiki/pagespec]] returns true if the page ends with
+> "[postcomment]" and the part before (e.g. sandbox) matches the glob. So, you can
+> have postcomment(blog/*) or something. (Perhaps instead of taking a glob, postcomment
+> should take a pagespec, so you can have postcomment(link(tags/commentable))?)
+>
+> This is why `anonok_pages => 'postcomment(*)'` and `locked_pages => '!postcomment(*)'`
+> are necessary to allow anonymous and logged-in editing (respectively).
+>
+> This is ugly - one alternative would be to add `check_permission()` that takes a
+> page and a verb (create, edit, rename, remove and maybe comment are the ones I
+> can think of so far), use that, and port the plugins you mentioned to use that
+> API too. This plugin could either call `check_can("$page/comment1", 'create')` or
+> call `check_can($page, 'comment')`.
+> 
+> One odd effect of the code structure I've used is that we check for the ability to
+> create the page before we actually know what page name we're going to use - when
+> posting the comment I just increment a number until I reach an unused one - so
+> either the code needs restructuring, or the permission check for 'create' would
+> always be for 'comment1' and never 'comment123'. --[[smcv]]
+
+>> Now resolved, in fact --[[smcv]]
+
+> Another possibility is to just check for permission to edit (e.g.) `sandbox/comment1`.
+> However, this makes the "comments can only be created, not edited" feature completely
+> reliant on the fact that internal pages can't be edited. Perhaps there should be a
+> `editable_pages` pagespec, defaulting to `'*'`? --[[smcv]]
+
+## comments directive vs global setting (resolved?)
+
+When comments have been enabled generally, you still need to mark which pages
+can have comments, by including the `\[[!comments]]` directive in them. By default,
+this directive expands to a "post a comment" link plus an `\[[!inline]]` with
+the comments. [This requirement has now been removed --[[smcv]]]
+
+> I don't like this, because it's hard to explain to someone why they have
+> to insert this into every post to their blog. Seems that the model used
+> for discussion pages could work -- if comments are enabled, automatically
+> add the comment posting form and comments to the end of each page.
+> --[[Joey]]
+
+>> I don't think I'd want comments on *every* page (particularly, not the
+>> front page). Perhaps a pagespec in the setup file, where the default is "*"?
+>> Then control freaks like me could use "link(tags/comments)" and tag pages
+>> as allowing comments.
+>>
+>>> Yes, I think a pagespec is the way to go. --[[Joey]]
+
+>>>> Implemented --[[smcv]]
+
+>> 
+>> The model used for discussion pages does require patching the existing
+>> page template, which I was trying to avoid - I'm not convinced that having
+>> every possible feature hard-coded there really scales (and obviously it's
+>> rather annoying while this plugin is on a branch). --[[smcv]]
+
+>>> Using the template would allow customising the html around the comments
+>>> which seems like a good thing? --[[Joey]]
+
+>>>> The \[[!comments]] directive is already template-friendly - it expands to
+>>>> the contents of the template `comments_embed.tmpl`, possibly with the
+>>>> result of an \[[!inline]] appended. I should change `comments_embed.tmpl`
+>>>> so it uses a template variable `INLINE` for the inline result rather than
+>>>> having the perl code concatenate it, which would allow a bit more
+>>>> customization (whether the "post" link was before or after the inline).
+>>>> Even if you want comments in page.tmpl, keeping the separate comments_embed.tmpl
+>>>> and having a `COMMENTS` variable in page.tmpl might be the way forward,
+>>>> since the smaller each templates is, the easier it will be for users
+>>>> to maintain a patched set of templates. (I think so, anyway, based on what happens
+>>>> with dpkg prompts in Debian packages with monolithic vs split
+>>>> conffiles.) --[[smcv]]
+
+>>>>> I've switched my branch to use page.tmpl instead; see what you think? --[[smcv]]
+
+## Raw HTML (resolved?)
+
+Raw HTML was not initially allowed by default (this was configurable).
+
+> I'm not sure that raw html should be a problem, as long as the
+> htmlsanitizer and htmlbalanced plugins are enabled. I can see filtering
+> out directives, as a special case. --[[Joey]]
+
+>> Right, if I sanitize each post individually, with htmlscrubber and either htmltidy
+>> or htmlbalance turned on, then there should be no way the user can forge a comment;
+>> I was initially wary of allowing meta directives, but I think those are OK, as long
+>> as the comment template puts the \[[!meta author]] at the *end*. Disallowing
+>> directives is more a way to avoid commenters causing expensive processing than
+>> anything else, at this point.
+>>
+>> I've rebased the plugin on master, made it sanitize individual posts' content
+>> and removed the option to disallow raw HTML. Sanitizing individual posts before
+>> they've been htmlized required me to preserve whitespace in the htmlbalance
+>> plugin, so I did that. Alternatively, we could htmlize immediately and always
+>> save out raw HTML? --[[smcv]]
+
+>>> There might be some use cases for other directives, such as img, in
+>>> comments.
+>>> 
+>>> I don't know if meta is "safe" (ie, guaranteed to be inexpensive and not
+>>> allow users to do annoying things) or if it will continue to be in the
+>>> future. Hard to predict really, all that can be said with certainty is
+>>> all directives will contine to be inexpensive and safe enough that it's
+>>> sensible to allow users to (ab)use them on open wikis.
+>>> --[[Joey]]