98 lines
3.1 KiB
Markdown
98 lines
3.1 KiB
Markdown
Sometimes you want to match a page only if it has certain properties. The use
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case I have in mind is this: show me all the pages that have children. You
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can't do that with a pagespec, so I created a plugin that adds some pagespec
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functions.
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`match_relative(blah)` will match a page x if a pagespec from x would match
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`blah`. This is only actually useful with relative pagespecs.
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`match_has_child(blah)` will match a child if it has a descendant named
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`blah`. If blah is empty, any child will match.
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So if I have:
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* foo
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* foo/blah
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* foo/bar
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* foo/bar/blah
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* foo/bar/bahoo
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* foo/baz
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* foo/baz/goo
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* foo/baz/goo/blah
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A pagespec `match_relative(./blah)` will match `foo/bar/bahoo`, because
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a pagespec of `./blah` from `bahoo` would match `foo/bar/blah`. A
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pagespec of `match_has_child(blah)` would match `foo`, `foo/bar`,
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`foo/baz`, and `foo/baz/goo`.
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Note that if you try to inline `*/blah` you will match `foo/blah`,
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`foo/bar/blah`, and `foo/baz/goo/blah` -- that is, the blah pages
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themselves rather than any relatives of theirs.
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This patch is useful for (among other things) constructing blogging
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systems where leaf nodes are organized hierarchically; using `has_child`,
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you can inline only leaf nodes and ignore "intermediate" nodes.
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`match_relative` can be used recursively to match properties of arbitrary
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complexity: "show me all the pages who have children called foo that
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have children called blah". I'm not sure what use it is, though.
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You can see the patch in action at
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<http://ikidev.betacantrips.com/conditionaltest/>,
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so named because I had hoped that something in conditional.pm could
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help me. I know the name "relative" sucks, feel free to come up with a
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better one. --Ethan
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<pre>
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diff -urNX ignorepats ikiwiki/IkiWiki/Plugin/relative.pm ikidev/IkiWiki/Plugin/relative.pm
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--- ikiwiki/IkiWiki/Plugin/relative.pm 1969-12-31 16:00:00.000000000 -0800
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+++ ikidev/IkiWiki/Plugin/relative.pm 2007-07-26 21:48:10.642686000 -0700
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@@ -0,0 +1,39 @@
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+#!/usr/bin/perl
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+# relative.pm: support for pagespecs on possible matches
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+package IkiWiki::Plugin::relative;
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+
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+use warnings;
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+use strict;
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+use IkiWiki 2.00;
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+
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+package IkiWiki::PageSpec;
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+
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+sub match_relative($$;@) {
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+ my $parent = shift;
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+ my $spec = shift;
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+ my %params = @_;
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+
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+ foreach my $page (keys %IkiWiki::pagesources) {
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+ next if $page eq $parent;
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+ if (IkiWiki::pagespec_match($page, $spec, location => $parent)) {
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+ return IkiWiki::SuccessReason->new("$parent can match $spec against $page");
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+ }
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+ }
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+ return IkiWiki::FailReason->new("$parent can't match $spec against anything");
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+}
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+
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+sub match_has_child($$;@) {
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+ my $page = shift;
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+ my $childname = shift;
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+ my $spec;
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+ if ($childname) {
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+ $spec = "$page/$childname or $page/*/$childname";
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+ }
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+ else {
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+ $spec = "$page/*";
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+ }
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+
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+ return match_relative($page, $spec, @_);
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+}
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+
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+1
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</pre>
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[[!tag patch]]
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> This looks really interesting. It reminds me of XPath and its conditionals.
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> Those might actually work well adapted to pagespecs. For instance, to write
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> "match any page with a child blah", you could just write *[blah] , or if you
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> don't want to use relative-by-default in the conditionals, *[./blah].
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> -- [[JoshTriplett]]
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