-[[!template id=gitbranch branch=smcv/sort-hooks author="[[Simon_McVittie|smcv]]"]]
[[!tag patch]]
The available [[ikiwiki/pagespec/sorting]] methods are currently hard-coded in
whether it would be worth making sort=name an alias for the current sort=title,
and changing the meaning of sort=title in 4.0, though).
-Gitweb:
-<http://git.pseudorandom.co.uk/smcv/ikiwiki.git?a=shortlog;h=refs/heads/sort-hooks>
+*[sort-hooks branch now withdrawn in favour of sort-package --s]*
I briefly tried to turn *all* the current sort types into hook functions, and
have some of them pre-registered, but decided that probably wasn't a good idea.
That earlier version of the branch is also available for comparison:
-<http://git.pseudorandom.co.uk/smcv/ikiwiki.git?a=shortlog;h=refs/heads/sort-hooks-excessive>
-
-(The older version is untested, and probably doesn't really work as-is - I
-misunderstood the details of how the built-in function `sort` works when using
-`$a` and `$b`. The newer version has been tested, and has a regression test for
-its core functionality.)
-
-This hook *isn't* (yet) sufficient to implement [[plugins/contrib/report]]'s
-NIH'd sorting mechanisms:
-
-* `report` can sort by any [[plugins/contrib/field]], whereas this one has a
- finite number of hooks: if the `field` plugin's functionality is desirable,
- perhaps parameterized sort mechanisms similar to pagespec match functions
- would be useful? Then the `field` plugin could register
- `hook(type => "sort", id => "field")` and you could have
- `\[[!inline ... sort="field(Mood)"]]` or something?
-
-* `report` can sort by multiple criteria, with independent direction-changing:
- if this is desirable, perhaps `pagespec_match_list` could be enhanced to
- interpret `sort="x -y z(w)"` as sorting by (pseudocode)
- `{ $cmp_x->($a, $b) || (-$cmp_y->($a, $b)) || $cmp_z->($a, $b, "w") }`?
-
-> I've now added both of these features to the sort-hooks branch. --[[smcv]]
+*[also withdrawn in favour of sort-package --s]*
>> I wonder if IkiWiki would benefit from the concept of a "sortspec", like a [[ikiwiki/PageSpec]] but dedicated to sorting lists of pages rather than defining lists of pages? Rather than defining a sort-hook, define a SortSpec class, and enable people to add their own sort methods as functions defined inside that class, similarly to the way they can add their own pagespec definitions. --[[KathrynAndersen]]
>>> share the `IkiWiki::PageSpec` package, but with a `cmp_` prefix. Gitweb:
>>> <http://git.pseudorandom.co.uk/smcv/ikiwiki.git?a=shortlog;h=refs/heads/sort-package>
-## Documentation from sort-hooks branch
-
-### sort hook (added to [[plugins/write]])
-
- hook(type => "sort", id => "foo", call => \&sort_by_foo);
-
-This hook adds an additional [[ikiwiki/pagespec/sorting]] order or overrides
-an existing one.
-
-The callback is given two page names followed by the parameter as arguments, and
-returns negative, zero or positive if the first page should come before,
-close to (i.e. undefined order), or after the second page.
-
-For instance, the built-in `title` sort order could be reimplemented as
-
- sub sort_by_title {
- pagetitle(basename($_[0])) cmp pagetitle(basename($_[1]));
- }
-
-and to sort by an arbitrary `meta` value, you could use:
-
- # usage: sort="meta(description)"
- sub sort_by_meta {
- my $param = $_[2];
- error "sort=meta requires a parameter" unless defined $param;
- my $left = $pagestate{$_[0]}{meta}{$param};
- $left = "" unless defined $left;
- my $right = $pagestate{$_[1]}{meta}{$param};
- $right = "" unless defined $right;
- return $left cmp $right;
- }
+>>>> I agree it seems more elegant, so I have focused on it.
+>>>>
+>>>> I don't know about reusing `IkiWiki::PageSpec` for this.
+>>>> --[[Joey]]
+
+>>>>> Fair enough, `IkiWiki::SortSpec::cmp_foo` would be just
+>>>>> as easy, or `IkiWiki::Sorting::cmp_foo` if you don't like
+>>>>> introducing "sort spec" in the API. I took a cue from
+>>>>> [[ikiwiki/pagespec/sorting]] being a subpage of
+>>>>> [[ikiwiki/pagespec]], and decided that yes, sorting is
+>>>>> a bit like a pagespec :-) Which name would you prefer? --s
+
+>>>>>> `SortSpec` --[[Joey]]
+
+>>>> I would be inclined to drop the `check_` stuff. --[[Joey]]
+
+>>>>> It basically exists to support `title_natural`, to avoid
+>>>>> firing up the whole import mechanism on every `cmp`
+>>>>> (although I suppose that could just be a call to a
+>>>>> memoized helper function). It also lets sort specs that
+>>>>> *must* have a parameter, like
+>>>>> [[field|plugins/contrib/field/discussion]], fail early
+>>>>> (again, not so valuable).
+>>>>>
+>>>>>> AFAIK, `use foo` has very low overhead when the module is already
+>>>>>> loaded. There could be some evalation overhead in `eval q{use foo}`,
+>>>>>> if so it would be worth addressing across the whole codebase.
+>>>>>> --[[Joey]]
+>>>>>
+>>>>> The former function could be achieved at a small
+>>>>> compatibility cost by putting `title_natural` in a new
+>>>>> `sortnatural` plugin (that fails to load if you don't
+>>>>> have `title_natural`), if you'd prefer - that's what would
+>>>>> have happened if `title_natural` was written after this
+>>>>> code had been merged, I suspect. Would you prefer this? --s
+
+>>>>>> Yes! (Assuming it does not make sense to support
+>>>>>> natural order sort of other keys than the title, at least..)
+>>>>>> --[[Joey]]
+
+>>>> Wouldn't it make sense to have `meta(title)` instead
+>>>> of `meta_title`? --[[Joey]]
+
+>>>>> Yes, you're right. I added parameters to support `field`,
+>>>>> and didn't think about making `meta` use them too.
+>>>>> However, `title` does need a special case to make it
+>>>>> default to the basename instead of the empty string.
+>>>>>
+>>>>> Another special case for `title` is to use `titlesort`
+>>>>> first (the name `titlesort` is derived from Ogg/FLAC
+>>>>> tags, which can have `titlesort` and `artistsort`).
+>>>>> I could easily extend that to other metas, though;
+>>>>> in fact, for e.g. book lists it would be nice for
+>>>>> `field(bookauthor)` to behave similarly, so you can
+>>>>> display "Douglas Adams" but sort by "Adams, Douglas".
+>>>>>
+>>>>> `meta_title` is also meant to be a prototype of how
+>>>>> `sort=title` could behave in 4.0 or something - sorting
+>>>>> by page name (which usually sorts in approximately the
+>>>>> same place as the meta-title, but occasionally not), while
+>>>>> displaying meta-titles, does look quite odd. --s
+
+>>>>>> Agreed. --[[Joey]]
+
+>>>> 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]]
+
+>>>>> No, `$2` is either `\w+\([^\)]*\)` or `[^\s]+` (with the
+>>>>> latter causing an error later if it doesn't also match `\w+`).
+>>>>> This branch doesn't add any parameterized sort methods,
+>>>>> in fact, although I did provide one on
+>>>>> [[field's_discussion_page|plugins/contrib/report/discussion]]. --s
+
+>>>> I wonder if it would make sense to add some combining keywords, so
+>>>> a sortspec reads like `sort="age then ascending title"`
+>>>> In a way, this reduces the amount of syntax that needs to be learned.
+>>>> I like the "then" (and it could allow other operations than
+>>>> simple combination, if any others make sense). Not so sure about the
+>>>> "ascending", which could be "reverse" instead, but "descending age" and
+>>>> "ascending age" both seem useful to be able to explicitly specify.
+>>>> --[[Joey]]
+
+>>>>> Perhaps. I do like the simplicity of [[KathrynAndersen]]'s syntax
+>>>>> from [[plugins/contrib/report]] (which I copied verbatim, except for
+>>>>> turning sort-by-`field` into a parameterized spec).
+>>>>>
+>>>>> If we're getting into English-like (or at least SQL-like) queries,
+>>>>> it might make sense to change the signature of the hook function
+>>>>> so it's a function to return a key, e.g.
+>>>>> `sub key_age { return -%pagemtime{$_[0]) }`. Then we could sort like
+>>>>> this:
+>>>>>
+>>>>> field(artistsort) or field(artist) or constant(Various Artists) then meta(titlesort) or meta(title) or title
+>>>>>
+>>>>> with "or" binding more closely than "then". Does this seem valuable?
+>>>>> I think the implementation would be somewhat more difficult. and
+>>>>> it's probably getting too complicated to be worthwhile, though?
+>>>>> (The keys that actually benefit from this could just
+>>>>> have smarter cmp functions, I think.)
+>>>>>
+>>>>> If the hooks return keys rather than cmp results, then we could even
+>>>>> have "lowercase" as an adjective used like "ascending"... maybe.
+>>>>> However, there are two types of adjective here: "lowercase"
+>>>>> really applies to the keys, whereas "ascending" applies to the "cmp"
+>>>>> result. Again, I think this is getting too complex, and could just
+>>>>> be solved with smarter cmp functions.
+>>>>>
+>>>>>> I agree. (Also, I think returning keys may make it harder to write
+>>>>>> smarter cmp functions.) --[[Joey]]
+>>>>>
+>>>>> Unfortunately, `sort="ascending mtime"` actually sorts by *descending*
+>>>>> timestamp (but`sort=age` is fine, because `age` could be defined as
+>>>>> now minus `ctime`). `sort=freshness` isn't right either, because
+>>>>> "sort by freshness" seems as though it ought to mean freshest first,
+>>>>> but "sort by ascending freshness" means put the least fresh first. If
+>>>>> we have ascending and descending keywords which are optional, I don't
+>>>>> think we really want different sort types to have different default
+>>>>> directions - it seems clearer to have `ascending` always be a no-op,
+>>>>> and `descending` always negate.
+>>>>>
+>>>>>> I think you've convinced me that ascending/descending impose too
+>>>>>> much semantics on it, so "-" is better. --[[Joey]]
+>>>>>
+>>>>> Perhaps we could borrow from `meta updated` and use `update_age`?
+>>>>> `updateage` would perhaps be a more normal IkiWiki style - but that
+>>>>> makes me think that updateage is a quantity analagous to tonnage or
+>>>>> voltage, with more or less recently updated pages being said to have
+>>>>> more or less updateage. I don't know whether that's good or bad :-)
+>>>>>
+>>>>> I'm sure there's a much better word, but I can't see it. Do you have
+>>>>> a better idea? --s
+## Documentation from sort-package branch
### meta_title sort order (conditionally added to [[ikiwiki/pagespec/sorting]])
> I feel it sould be clearer to call that "sortas", since "sort=" is used
> to specify a sort method in other directives. --[[Joey]]
+ >> Fair enough, that's easy to do. --[[smcv]]
+
### Multiple sort orders (added to [[ikiwiki/pagespec/sorting]])
In addition, you can combine several sort orders and/or reverse the order of
\[[!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:
+> I now realise that `author` should also have this, again for use
+> with (Western) names. --s
-### Sorting plugins
+### Sorting plugins (added to [[plugins/write]])
Similarly, it's possible to write plugins that add new functions as
[[ikiwiki/pagespec/sorting]] methods. To achieve this, add a function to
sipb-www / ikiwiki.git / blobdiff