diff options
| -rw-r--r-- | doc/todo/allow_plugins_to_add_sorting_methods.mdwn | 163 |
1 files changed, 94 insertions, 69 deletions
diff --git a/doc/todo/allow_plugins_to_add_sorting_methods.mdwn b/doc/todo/allow_plugins_to_add_sorting_methods.mdwn index e1e05e81c..156678da7 100644 --- a/doc/todo/allow_plugins_to_add_sorting_methods.mdwn +++ b/doc/todo/allow_plugins_to_add_sorting_methods.mdwn @@ -1,4 +1,3 @@ -[[!template id=gitbranch branch=smcv/sort-hooks author="[[Simon_McVittie|smcv]]"]] [[!tag patch]] The available [[ikiwiki/pagespec/sorting]] methods are currently hard-coded in @@ -11,36 +10,13 @@ title over the page name, but for compatibility, I'm not going to (I do wonder 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 +*[sort-hooks branch now withdrawn in favour of sort-package --s]* I briefly tried to turn *all* the current sort types into hook functions, and have some of them pre-registered, but decided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 --[[smcv]] +*[also withdrawn in favour of sort-package --s]* 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]] @@ -53,17 +29,65 @@ NIH'd sorting mechanisms: >>>> 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 :-) --s + >>>> I would be inclined to drop the `check_` stuff. ->>>> + +>>>>> 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). +>>>>> +>>>>> 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. --s + >>>> Wouldn't it make sense to have `meta(title)` instead ->>>> of `meta_title`? ->>>> +>>>> of `meta_title`? --J + +>>>>> 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 + >>>> 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. ->>>> +>>>> do not need parameters. --J + +>>>>> 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. @@ -73,38 +97,42 @@ NIH'd sorting mechanisms: >>>> "ascending age" both seem useful to be able to explicitly specify. >>>> --[[Joey]] -## 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; - } +>>>>> Perhaps. I do like the simplicity of [[KathyrnAndersen]]'s syntax +>>>>> from [[plugins/contrib/report]] (which I copied verbatim, except for +>>>>> turning sort-by-`field` into a parameterized spec), and I can't really +>>>>> think of any sensible way to combine sort specs other than "sort by a, +>>>>> break ties by b, ...", possibly with some reversals thrown in. +>>>>> +>>>>> If no other combinations do make sense, is your proposal that "then" +>>>>> is entirely redundant (easy, just make it a predefined sort spec that +>>>>> returns 0!), or that it's mandatory "punctuation" (add an explicit +>>>>> check, or make "then" expand to "||" and let Perl fail to compile +>>>>> the generated code if it's omitted)? +>>>>> +>>>>> It is a little unfortunate that reversal has to move into the sort +>>>>> spec - I prefer `reverse=yes` - but that's necessary for multi-level +>>>>> sorting. I can see your point about ascending/descending being more +>>>>> obvious to look at, but they're also considerably more verbose. +>>>>> +>>>>> 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. +>>>>> +>>>>> 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. --s +## Documentation from sort-package branch ### meta_title sort order (conditionally added to [[ikiwiki/pagespec/sorting]]) @@ -115,6 +143,8 @@ and to sort by an arbitrary `meta` value, you could use: > 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 @@ -130,12 +160,7 @@ An optional `sort` parameter will be used preferentially when \[[!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 +### 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 |