1 I'd like to see some way to conditionally include wiki text based on
2 whether the wiki enables or disables certain features. For example,
3 [[ikiwiki/formatting]], could use `\[[!if (enabled smiley) """Also, because
4 this wiki has the smiley plugin enabled, you can insert \[[smileys]] and
5 some other useful symbols."""]]`, and a standard template for [[plugins]]
6 pages could check for the given plugin name to print "enabled" or
9 Some potentially useful conditionals:
11 * `enabled pluginname`
12 * `disabled pluginname`
13 * `any pagespec`: true if any of the pages in the [[ikiwiki/PageSpec]] exist
14 * `all pagespec`: true if all of the pages in the [[ikiwiki/PageSpec]] exist
15 * `no pagespec` or `none pagespec`: true if none of the pages in the [[ikiwiki/PageSpec]] exist
16 * `thispage pagespec`: true if pagespec includes the page getting rendered (possibly one including the page with this content on it).
17 * `sourcepage pagespec`: true if pagespec includes the page corresponding to the file actually containing this content, rather than a page including it.
18 * `included`: true if included on another page, via [[plugins/inline]], [[plugins/sidebar]], [[plugins/contrib/navbar]], etc.
20 You may or may not want to include boolean operations (`and`, `or`, and
21 `not`); if you do, you could replace `disabled` with `not enabled`, and `no
22 pagespec` or `none pagespec` with `not any pagespec` (but you may want to
23 keep the aliases for simplicity anyway). You also may or may not want to
24 include an `else` clause; if so, you could label the text used if true as
27 Syntax could vary greatly here, both for the
28 [[ikiwiki/Directive]] and for the condition itself.
30 > I think this is a good thing to consider, although conditionals tend to
31 > make everything a lot more complicated, so I also want to KISS, and not
32 > use too many of them.
34 > I'd probably implement this using the same method as pagespecs, so 'and',
35 > 'or', '!', and paren groupings work.
37 > It could be thought of as simply testing to see if a pagespec matches
38 > anything, using a slightly expanded syntax for the pagespec, which would
39 > also allow testing for things like link(somepage),
40 > created_before(somepage), etc.
42 > That also gives us your "any pagespec" for free: "page or page or page".
43 > And for "all pagespec", you can do "page and page and page".
45 > For plugins testing, maybe just use "enabled(name)"?
47 > I'm not sure what the use cases are for thispage, sourcepage, and
48 > included. I don't know if the included test is even doable. I'd be
49 > inclined to not bother with these three unless there are use cases I'm
52 > As to the syntax, to fit it into standard preprocessor syntax, it would
53 > need to look something like this:
55 > \[[!if test="enabled(smiley)" """foo"""]]
59 >> [[ikiwiki/PageSpec]] syntax seems perfect, and your proposed syntax for the `if`
60 >> [[ikiwiki/Directive]] looks fine to me.
62 >> [[ikiwiki/PageSpec]]s don't give you `none` for free, since `!foo/*` as a boolean
63 >> would mean "does any page not matching `foo/*` exist", not "does `foo/*`
64 >> match nothing"; however, I don't really care much about `none`, since I
65 >> just threw it in while brainstorming, and I don't know any compelling use
68 >> `enabled(pluginname)` will work perfectly, and `!enabled(pluginname)`
69 >> makes `disabled` unnecessary.
71 >> A few use cases for `included`, which I would really like to see:
73 >> * On the sidebar page, you could say something like \[[!if test="!included"
74 >> """This page, without this help message, appears as a sidebar on all
75 >> pages."""]]. The help text would then only appear on the sidebar page
76 >> itself, not the sidebar included on all pages.
78 >> * On [[blog]] entries, you could use `included` to implement a cut.
79 >> (Please don't take that as an argument against. :) ) For instance, you
80 >> could use included rather than [[plugins/toggle]] for the detailed
81 >> changelogs of ikiwiki, or to embed an image as a link in the feed rather
82 >> than an embedded image.
84 >> Some use cases for `thispage`:
86 >> * You could use `thispage` to include or exclude parts of the sidebar based
87 >> on the page you include it in. You can already use subpages/sidebar for
88 >> subpages/*, but `thispage` seems more flexible, makes it trivial to have
89 >> common portions rather than using [[plugins/inline]] with the `raw`
90 >> option, and keeps the sidebar in one place.
92 >> * You could use `thispage` to implement multiple different feeds for the
93 >> same content with slightly different presentation. For instance, using
94 >> templates for image inclusion, you could offer a feed with image links
95 >> and a feed with embedded images. Similarly, using templates for cuts, you
96 >> could offer a feed with cuts and a feed with full content in every post.
98 >> I don't have any particular attachment to `sourcepage`. It only makes
99 >> sense as part of a template, since otherwise you know the source page when
102 >> --[[JoshTriplett]]
104 This is now completely [[todo/done]]! See [[plugins/conditional]].
108 > You rock mightily. --[[JoshTriplett]]
110 Is there a way to test features other than plugins? For example,
111 to add to [[ikiwiki/Markdown]] something like
113 \[[!if test="enabled(multimarkdown)" then="You can also use..."]]
115 (I tried it like that just to see if it would work, but I wasn't that lucky.)
118 > No, not supported. I really think that trying to conditionalise text on a
119 > page for multimarkdown is a path to madness or unreadability though.
120 > Perhaps it would be better to have .mmdwn files that can only contain
121 > multimarkdown? --[[Joey]]
123 >> Really, there was only one (or maybe two) pages I had in mind as appropriate
124 >> places for conditional text based on multimarkdown—the underlay pages
125 >> for 'markdown' and maybe also 'formatting', because those are the pages you
126 >> look at when you're trying to find out how to mark stuff up for the wiki, so
127 >> if MM is enabled, they need to at least mention it and have a link to the
128 >> MM syntax guide.--ChapmanFlack