[[tag wishlist]]

# Context

I may have missed a simple way to achieve what I need without
modifying ikiwiki, so here is the context.

I have a first-level directory (called `bricks`) containing a bunch of
wiki pages :

    /bricks
     |
     |- bla.mdwn
     |
     |- bli.mdwn
     |
     `- ...

I have two groups of tags called `direction` and `usage`, stored in
two sub-directories of `$tagbase` :

    /tag
     |
     |- direction
     |    |- d1.mdwn
     |    |- d2.mdwn
     |    |- ...
     |
     |- usage
     |    |- u1.mdwn
     |    |- u2.mdwn
     |    |- ...

Any page in `/brick` can be tagged with one or more tags from any of
these tags-groups.

I need to present different views for these wiki pages, so a `/view`
tree is dedicated to this mission :

    /view
     |
     |- dev
     |   |- d1.mdwn
     |   |- d2.mdwn
     |   |-...
     |
     |- howto
         |- u1.mdwn
         |- u2.mdwn
         |- ...

... where e.g. `/view/dev/d1` lists a subset (depending on other tags)
of the pages tagged d1.

My current plan is :

- thanks to the pagetemplate plugin, `/view/dev/*` and `/view/howto/*` would be assigned two custom templates, containing respectively `\[[template id=dev_direction]]` and `\[[template id=howto_usage]]`
- `/templates/dev_direction.mdwn` and `/templates/howto_usage.mdwn` would use `\[[!map ...]]` directives to build their views

# My issue

Such map directives would look something like the following (more
complicated, actually, but let's focus on my current issue) :

	\[[!map pages="bricks/* and link(tag/usage/<TMPL_VAR BASENAME>)"]]

Where `BASENAME` value would be, e.g., `u1` or `d2`, depending on the
page inserting the template. But `BASENAME` does not exist. I found
that `<TMPL_VAR PAGE>` is replaced with the full path to the page, but
I did not found how to get the page's basename in a template included
with a `\[[template id=...]]` directive.

Any idea ?

I guess it would be possible to provide the templates inserted by the
template plugin with more `TMPL_VAR` variables, but I don't know ikiwiki
codebase well, so I don't know how hard it would be.

I sure could write a ad-hoc plugin that would use the pagetemplate
hook to add a custom `<TMPL_LOOP>` selector I could use in my
templates, or another one that would use the filter hook to add the
needed `\[[!map ...]]` where it belongs to, but since ikiwiki's
preprocessor directives already *almost* do what I need, I'd like to
avoid the ad-hoc plugin solution.

(Adding a parameter such as `name=d1` in every `/view/dev/d*.mdwn` and
`/view/howto/u*.mdwn` page is not an option : there may be quite
a few, that's why I intend to use the pagetemplate plugin in the first
place to assign them a common template.)

More or less OT: I've not checked the compatibility of pagetemplate
and template plugins yet; can a template (`*.tmpl`), assigned by
pagetemplate, itself call a template (`*.mdwn`) managed by the
template plugin ? The hooks call order tends to make me think it is
not possible, which anyway would ruin my current plan.