X-Git-Url: https://sipb.mit.edu/gitweb.cgi/ikiwiki.git/blobdiff_plain/81cd30690024db1fc0b300e3a09504f1c613be21..9e7dcefd7ed9424de20706f63c7bab5182c5df78:/doc/todo/allow_plugins_to_add_sorting_methods.mdwn

diff --git a/doc/todo/allow_plugins_to_add_sorting_methods.mdwn b/doc/todo/allow_plugins_to_add_sorting_methods.mdwn
index 419a73419..67d85f6f8 100644
--- a/doc/todo/allow_plugins_to_add_sorting_methods.mdwn
+++ b/doc/todo/allow_plugins_to_add_sorting_methods.mdwn
@@ -44,10 +44,28 @@ NIH'd sorting mechanisms:
 
 >> I wonder if IkiWiki would benefit from the concept of a "sortspec", like a [[ikiwiki/PageSpec]] but dedicated to sorting lists of pages rather than defining lists of pages?  Rather than defining a sort-hook, define a SortSpec class, and enable people to add their own sort methods as functions defined inside that class, similarly to the way they can add their own pagespec definitions. --[[KathrynAndersen]]
 
->>> I'd be inclined to think that's overkill, but it probably wouldn't be
->>> all that hard to implement... Joey? Any thoughts? --s
-
-## Documentation extracted from the branch
+>>> [[!template id=gitbranch branch=smcv/sort-package author="[[Simon_McVittie|smcv]]"]]
+>>> I'd be inclined to think that's overkill, but it wasn't very hard to
+>>> implement, and in a way is more elegant. I set it up so sort mechanisms
+>>> share the `IkiWiki::PageSpec` package, but with a `cmp_` prefix. Gitweb:
+>>> <http://git.pseudorandom.co.uk/smcv/ikiwiki.git?a=shortlog;h=refs/heads/sort-package>
+
+>>>> I agree it seems more elegant, so I have focused on it.
+>>>>
+>>>> I don't know about reusing `IkiWiki::PageSpec` for this.
+>>>>
+>>>> I would be inclined to drop the `check_` stuff.
+>>>>
+>>>> Wouldn't it make sense to have `meta(title)` instead
+>>>> of `meta_title`?
+>>>>
+>>>> As I read the regexp in `cmpspec_translate`, the "command"
+>>>> is required to have params. They should be optional, 
+>>>> to match the documentation and because most sort methods
+>>>> do not need parameters.
+>>>> --[[Joey]]
+
+## Documentation from sort-hooks branch
 
 ### sort hook (added to [[plugins/write]])
 
@@ -86,6 +104,9 @@ and to sort by an arbitrary `meta` value, you could use:
   or `\[[!meta title="foo"]]` [[ikiwiki/directive]], or the page name if no
   full title was set.
 
+  > I feel it sould be clearer to call that "sortas", since "sort=" is used
+  > to specify a sort method in other directives. --[[Joey]]
+
 ### Multiple sort orders (added to [[ikiwiki/pagespec/sorting]])
 
 In addition, you can combine several sort orders and/or reverse the order of
@@ -100,3 +121,31 @@ An optional `sort` parameter will be used preferentially when
        \[[!meta title="The Beatles" sort="Beatles, The"]]
 
        \[[!meta title="David Bowie" sort="Bowie, David"]]
+
+## Documentation from sort-package branch
+
+The changes to [[ikiwiki/pagespec/sorting]] are the same.
+The changes to [[plugins/write]] are replaced by:
+
+### Sorting plugins
+
+Similarly, it's possible to write plugins that add new functions as
+[[ikiwiki/pagespec/sorting]] methods. To achieve this, add a function to
+the IkiWiki::PageSpec package named `cmp_foo`, which will be used when sorting
+by `foo` or `foo(...)` is requested.
+
+The function will be passed three or more parameters. The first two are
+page names, and the third is `undef` if invoked as `foo`, or the parameter
+`"bar"` if invoked as `foo(bar)`. It may also be passed additional, named
+parameters.
+
+It should return the same thing as Perl's `cmp` and `<=>` operators: negative
+if the first argument is less than the second, positive if the first argument
+is greater, or zero if they are considered equal. It may also raise an
+error using `error`, for instance if it needs a parameter but one isn't
+provided.
+
+You can also define a function called `check_cmp_foo` in the same package.
+If you do, it will be called while preparing to sort by `foo` or `foo(bar)`,
+with argument `undef` or `"bar"` respectively; it may raise an error using
+`error`, if sorting like that isn't going to work.