> One way to do this would be to introduce variables into the pagespec, along with
> universal and/or existential [[!wikipedia Quantification]]. That looks quite complex.
>
+>> I thought about this briefly, and got about that far.. glad you got
+>> further. :-) --[[Joey]]
+>
> Another option would be go with a more functional syntax. The concept here would
> be to allow a pagespec to appear in a 'pagespec function' anywhere a page can. e.g.
> I could pass a pagespec to `link()` and that would return true if there is a link to any
> ends, and that isn't a regular language (we can't use regular expression matching for
> easy parsing).
>
+>> Also, it may cause ambiguities with page names that contain parens
+>> (though some such ambigutities already exist with the pagespec syntax).
+>
> One simplification of that would be to introduce some pagespec [[shortcuts]]. We could
> then allow pagespec functions to take either pages, or named pagespec shortcuts. The
> pagespec shortcuts would just be listed on a special page, like current [[shortcuts]].
> Does that seem like a reasonable first approach?
>
> -- [[Will]]
+
+>> Having a separate page for the shortcuts feels unwieldly.. perhaps
+>> instead the shortcut could be defined earlier in the scope of the same
+>> pagespec that uses it?
+>>
+>> Example: `define(~bugs, bugs/* and !*/Discussion) and define(~openbugs, ~bugs and !link(done)) and ~openbugs and !link(~openbugs)`
+
+>>> That could work. parens are only ever nested 1 deep in that grammar so it is regular and the current parsing would be ok.
+
+>> Note that I made the "~" explicit, not implicit, so it could be left out. In the case of ambiguity between
+>> a definition and a page name, the definition would win.
+
+>>> That was my initial thought too :), but when implementing it I decided that requiring the ~ made things easier. I'll probably require the ~ for the first pass at least.
+
+>> So, equivilant example: `define(bugs, bugs/* and !*/Discussion) and define(openbugs, bugs and !link(done)) and openbugs and !link(openbugs)`
+>>
+>> Re recursion, it is avoided.. but building a pagespec that is O(N^X) where N is the
+>> number of pages in the wiki is not avoided. Probably need to add DOS prevention.
+>> --[[Joey]]
+
+>>> If you memoize the outcomes of the named pagespecs you can make in O(N.X), no?
+>>> -- [[Will]]
+
+>>>> Yeah, guess that'd work. :-)
+
+> One quick further thought. All the above discussion assumes that 'dependency' is the
+> same as 'links to', which is not really true. For example, you'd like to be able to say
+> "This bug does not depend upon [ [ link to other bug ] ]" and not have a dependency.
+> Without having different types of links, I don't see how this would be possible.
+>
+> -- [[Will]]
+
+Okie - I've had a quick attempt at this. Initial patch attached. This one doesn't quite work.
+And there is still a lot of debugging stuff in there.
+
+At the moment I've added a new preprocessor plugin, `definepagespec`, which is like
+shortcut for pagespecs. To reference a named pagespec, use `~` like this:
+
+ [ [!definepagespec name="bugs" spec="bugs/* and !*/Discussion"]]
+ [ [!definepagespec name="openbugs" spec="~bugs and !link(done)"]]
+ [ [!definepagespec name="readybugs" spec="~openbugs and !link(~openbugs)"]]
+
+At the moment the problem is in `match_link()` when we're trying to find a sub-page that
+matches the appropriate page spec. There is no good list of pages available to iterate over.
+
+ foreach my $nextpage (keys %IkiWiki::pagesources)
+
+does not give me a good list of pages. I found the same thing when I was working on
+this todo [[todo/Add_a_plugin_to_list_available_pre-processor_commands]].
+
+> I'm not sure why iterating over `%pagesources` wouldn't work here, it's the same method
+> used by anything that needs to match a pagespec against all pages..? --[[Joey]]
+
+>> My uchecked hypothesis is that %pagesources is created after the refresh hook.
+>> I've also been concerned about how globally defined pagespec shortcuts would interact with
+>> the page dependancy system. Your idea of internally defined shortcuts should fix that. -- [[Will]]
+
+>>> You're correct, the refresh hook is run very early, before pagesources
+>>> is populated. (It will be partially populated on a refresh, but will
+>>> not be updated to reflect new pages.) Agree that internally defined
+>>> seems the way to go. --[[Joey]]
+
+Immediately below is a patch which seems to basically work. Lots of debugging code is still there
+and it needs a cleanup, but I thought it worth posting at this point. (I was having problems
+with old style glob lists, so i just switched them off for the moment.)
+
+The following three inlines work for me with this patch:
+
+ Bugs:
+
+ [ [!inline pages="define(~bugs, bugs/* and ! */Discussion) and ~bugs" archive="yes"]]
+
+ OpenBugs:
+
+ [ [!inline pages="define(~bugs, bugs/* and ! */Discussion) and define(~openbugs,~bugs and !link(done)) and ~openbugs" archive="yes"]]
+
+ ReadyBugs:
+
+ [ [!inline pages="define(~bugs, bugs/* and ! */Discussion) and define(~openbugs,~bugs and !link(done)) and define(~readybugs,~openbugs and !link(~openbugs)) and ~readybugs" archive="yes"]]
+
+----
+
+diff --git a/IkiWiki.pm b/IkiWiki.pm
+index e476521..07b71d7 100644
+--- a/IkiWiki.pm
++++ b/IkiWiki.pm
+@@ -1524,7 +1524,7 @@ sub globlist_to_pagespec ($) { #{{{
+
+ sub is_globlist ($) { #{{{
+ my $s=shift;
+- return ( $s =~ /[^\s]+\s+([^\s]+)/ && $1 ne "and" && $1 ne "or" );
++ return 0; #( $s =~ /[^\s]+\s+([^\s]+)/ && $1 ne "and" && $1 ne "or" );
+ } #}}}
+
+ sub safequote ($) { #{{{
+@@ -1605,7 +1605,7 @@ sub pagespec_merge ($$) { #{{{
+ return "($a) or ($b)";
+ } #}}}
+
+-sub pagespec_translate ($) { #{{{
++sub pagespec_makeperl ($) { #{{{
+ my $spec=shift;
+
+ # Support for old-style GlobLists.
+@@ -1624,9 +1624,11 @@ sub pagespec_translate ($) { #{{{
+ |
+ \) # )
+ |
+- \w+\([^\)]*\) # command(params)
++ define\(\s*~\w+\s*,((\([^\(\)]*\)) | ([^\(\)]+))+\) # define(~specName, spec) - spec can contain parens 1 deep
++ |
++ \w+\([^\(\)]*\) # command(params) - params cannot contain parens
+ |
+- [^\s()]+ # any other text
++ [^\s\(\)]+ # any other text
+ )
+ \s* # ignore whitespace
+ }igx) {
+@@ -1640,16 +1642,23 @@ sub pagespec_translate ($) { #{{{
+ elsif ($word eq "(" || $word eq ")" || $word eq "!") {
+ $code.=' '.$word;
+ }
++ elsif ($word =~ /^define\(\s*~(\w+)\s*,(.*)\)$/) {
++ $code .= " (\$specFuncsRef->{$1}=";
++ #$code .= "memoize(";
++ $code .= pagespec_makeperl($2);
++ #$code .= ")";
++ $code .= ") ";
++ }
+ elsif ($word =~ /^(\w+)\((.*)\)$/) {
+ if (exists $IkiWiki::PageSpec::{"match_$1"}) {
+- $code.="IkiWiki::PageSpec::match_$1(\$page, ".safequote($2).", \@_)";
++ $code.="IkiWiki::PageSpec::match_$1(\$page, \$specFuncsRef, ".safequote($2).", \@_)";
+ }
+ else {
+ $code.=' 0';
+ }
+ }
+ else {
+- $code.=" IkiWiki::PageSpec::match_glob(\$page, ".safequote($word).", \@_)";
++ $code.=" IkiWiki::PageSpec::match_glob(\$page, \$specFuncsRef, ".safequote($word).", \@_)";
+ }
+ }
+
+@@ -1657,8 +1666,18 @@ sub pagespec_translate ($) { #{{{
+ $code=0;
+ }
+
++ return 'sub { my $page=shift; my $specFuncsRef=shift; '.$code.' }';
++} #}}}
++
++sub pagespec_translate ($) { #{{{
++ my $spec=shift;
++
++ my $code = pagespec_makeperl($spec);
++
++ print "Spec '$spec' led to perl '$code'\n";
++
+ no warnings;
+- return eval 'sub { my $page=shift; '.$code.' }';
++ return eval $code;
+ } #}}}
+
+ sub pagespec_match ($$;@) { #{{{
+@@ -1673,7 +1692,7 @@ sub pagespec_match ($$;@) { #{{{
+
+ my $sub=pagespec_translate($spec);
+ return IkiWiki::FailReason->new("syntax error in pagespec \"$spec\"") if $@;
+- return $sub->($page, @params);
++ return $sub->($page, {}, @params);
+ } #}}}
+
+ sub pagespec_valid ($) { #{{{
+@@ -1722,13 +1741,77 @@ sub new { #{{{
+
+ package IkiWiki::PageSpec;
+
+-sub match_glob ($$;@) { #{{{
++sub check_named_spec($$$;@) {
++ my $page=shift;
++ my $specFuncsRef=shift;
++ my $specName=shift;
++ my %params=@_;
++
++ return IkiWiki::FailReason->new("Named page spec '$specName' is not valid")
++ unless (substr($specName, 0, 1) eq '~');
++
++ $specName = substr($specName, 1);
++ print "Checking pagespec named $specName against page $page\n";
++ if (exists $specFuncsRef->{$specName}) {
++ # remove the named spec from the spec refs
++ # when we recurse to avoid infinite recursion
++ my $sub = $specFuncsRef->{$specName};
++ $specFuncsRef->{$specName} = undef;
++ my $result = $sub->($page, $specFuncsRef, %params);
++ $specFuncsRef->{$specName} = $sub;
++ return $result;
++ } else {
++ print "Couldn't find pagespec\n";
++ return IkiWiki::FailReason->new("Page spec $specName does not exist");
++ }
++}
++
++sub check_named_spec_existential($$$$;@) {
++ my $page=shift;
++ my $specFuncsRef=shift;
++ my $specName=shift;
++ my $funcref=shift;
++ my %params=@_;
++
++ return IkiWiki::FailReason->new("Named page spec '$specName' is not valid")
++ unless (substr($specName, 0, 1) eq '~');
++ $specName = substr($specName, 1);
++
++ print "Checking (existential) pagespec named $specName against page $page\n";
++
++ if (exists $specFuncsRef->{$specName}) {
++ # remove the named spec from the spec refs
++ # when we recurse to avoid infinite recursion
++ my $sub = $specFuncsRef->{$specName};
++ $specFuncsRef->{$specName} = undef;
++
++ foreach my $nextpage (keys %IkiWiki::pagesources) {
++ print "Checking $nextpage against $specName\n";
++ if ($sub->($nextpage, $specFuncsRef, %params)) {
++ print "Match! Checking spec $nextpage against function from original page $page\n";
++ my $tempResult = $funcref->($page, $specFuncsRef, $nextpage, %params);
++ return $tempResult if ($tempResult);
++ }
++ }
++
++ $specFuncsRef->{$specName} = $sub;
++ return IkiWiki::FailReason->new("No page in spec $specName was successfully matched");
++ } else {
++ print "Couldn't find pagespec\n";
++ return IkiWiki::FailReason->new("Page spec $specName does not exist");
++ }
++}
++
++sub match_glob ($$$;@) { #{{{
+ my $page=shift;
++ my $specFuncsRef=shift;
+ my $glob=shift;
+ my %params=@_;
+
+ my $from=exists $params{location} ? $params{location} : '';
+
++ print "Matching glob $glob \n";
++
+ # relative matching
+ if ($glob =~ m!^\./!) {
+ $from=~s#/?[^/]+$##;
+@@ -1736,6 +1819,10 @@ sub match_glob ($$;@) { #{{{
+ $glob="$from/$glob" if length $from;
+ }
+
++ if (substr($glob, 0, 1) eq '~') {
++ return check_named_spec($page, $specFuncsRef, $glob);
++ }
++
+ my $regexp=IkiWiki::glob2re($glob);
+ if ($page=~/^$regexp$/i) {
+ if (! IkiWiki::isinternal($page) || $params{internal}) {
+@@ -1750,17 +1837,29 @@ sub match_glob ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_internal ($$;@) { #{{{
+- return match_glob($_[0], $_[1], @_, internal => 1)
++sub match_internal ($$$;@) { #{{{
++ my $page=shift;
++ my $specFuncsRef=shift;
++ my $glob=shift;
++
++ return match_glob($page, $specFuncsRef, $glob, @_, internal => 1)
+ } #}}}
+
+-sub match_link ($$;@) { #{{{
++sub match_link ($$$;@) { #{{{
+ my $page=shift;
+- my $link=lc(shift);
++ my $specFuncsRef=shift;
++ my $fulllink=shift;
++ my $link=lc($fulllink);
+ my %params=@_;
+
++ print "Matching link $fulllink \n";
++
+ my $from=exists $params{location} ? $params{location} : '';
+
++ if (substr($fulllink, 0, 1) eq '~') {
++ return check_named_spec_existential($page, $specFuncsRef, $fulllink, \&match_link);
++ }
++
+ # relative matching
+ if ($link =~ m!^\.! && defined $from) {
+ $from=~s#/?[^/]+$##;
+@@ -1784,12 +1883,16 @@ sub match_link ($$;@) { #{{{
+ return IkiWiki::FailReason->new("$page does not link to $link");
+ } #}}}
+
+-sub match_backlink ($$;@) { #{{{
+- return match_link($_[1], $_[0], @_);
++sub match_backlink ($$$;@) { #{{{
++ my $page=shift;
++ my $specFuncsRef=shift;
++ my $backlink=shift;
++ return match_link($backlink, $specFuncsRef, $page, @_);
+ } #}}}
+
+-sub match_created_before ($$;@) { #{{{
++sub match_created_before ($$$;@) { #{{{
+ my $page=shift;
++ my $specFuncsRef=shift;
+ my $testpage=shift;
+
+ if (exists $IkiWiki::pagectime{$testpage}) {
+@@ -1805,8 +1908,9 @@ sub match_created_before ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_created_after ($$;@) { #{{{
++sub match_created_after ($$$;@) { #{{{
+ my $page=shift;
++ my $specFuncsRef=shift;
+ my $testpage=shift;
+
+ if (exists $IkiWiki::pagectime{$testpage}) {
+@@ -1822,8 +1926,12 @@ sub match_created_after ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_creation_day ($$;@) { #{{{
+- if ((gmtime($IkiWiki::pagectime{shift()}))[3] == shift) {
++sub match_creation_day ($$$;@) { #{{{
++ my $page=shift;
++ shift;
++ my $time=shift;
++
++ if ((gmtime($IkiWiki::pagectime{$page}))[3] == $time) {
+ return IkiWiki::SuccessReason->new('creation_day matched');
+ }
+ else {
+@@ -1831,8 +1939,12 @@ sub match_creation_day ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_creation_month ($$;@) { #{{{
+- if ((gmtime($IkiWiki::pagectime{shift()}))[4] + 1 == shift) {
++sub match_creation_month ($$$;@) { #{{{
++ my $page=shift;
++ shift;
++ my $time=shift;
++
++ if ((gmtime($IkiWiki::pagectime{$page}))[4] + 1 == $time) {
+ return IkiWiki::SuccessReason->new('creation_month matched');
+ }
+ else {
+@@ -1840,8 +1952,12 @@ sub match_creation_month ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_creation_year ($$;@) { #{{{
+- if ((gmtime($IkiWiki::pagectime{shift()}))[5] + 1900 == shift) {
++sub match_creation_year ($$$;@) { #{{{
++ my $page=shift;
++ shift;
++ my $time=shift;
++
++ if ((gmtime($IkiWiki::pagectime{$page}))[5] + 1900 == $time) {
+ return IkiWiki::SuccessReason->new('creation_year matched');
+ }
+ else {
+diff --git a/IkiWiki/Plugin/attachment.pm b/IkiWiki/Plugin/attachment.pm
+index f1f792a..a410e48 100644
+--- a/IkiWiki/Plugin/attachment.pm
++++ b/IkiWiki/Plugin/attachment.pm
+@@ -291,7 +291,8 @@ sub attachment_list ($) { #{{{
+
+ package IkiWiki::PageSpec;
+
+-sub match_user ($$;@) { #{{{
++sub match_user ($$$;@) { #{{{
++ shift;
+ shift;
+ my $user=shift;
+ my %params=@_;
+@@ -311,7 +312,8 @@ sub match_user ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_ip ($$;@) { #{{{
++sub match_ip ($$$;@) { #{{{
++ shift;
+ shift;
+ my $ip=shift;
+ my %params=@_;
+diff --git a/IkiWiki/Plugin/conditional.pm b/IkiWiki/Plugin/conditional.pm
+index 7716fce..2110ca0 100644
+--- a/IkiWiki/Plugin/conditional.pm
++++ b/IkiWiki/Plugin/conditional.pm
+@@ -70,7 +70,8 @@ sub preprocess_if (@) { #{{{
+
+ package IkiWiki::PageSpec;
+
+-sub match_enabled ($$;@) { #{{{
++sub match_enabled ($$$;@) { #{{{
++ shift;
+ shift;
+ my $plugin=shift;
+
+@@ -83,13 +84,14 @@ sub match_enabled ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_sourcepage ($$;@) { #{{{
++sub match_sourcepage ($$$;@) { #{{{
+ shift;
++ my $specFuncsRef=shift;
+ my $glob=shift;
+ my %params=@_;
+
+ return IkiWiki::FailReason->new("cannot match sourcepage") unless exists $params{sourcepage};
+- if (match_glob($params{sourcepage}, $glob, @_)) {
++ if (match_glob($params{sourcepage}, $specFuncsRef, $glob, @_)) {
+ return IkiWiki::SuccessReason->new("sourcepage matches $glob");
+ }
+ else {
+@@ -97,13 +99,14 @@ sub match_sourcepage ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_destpage ($$;@) { #{{{
++sub match_destpage ($$$;@) { #{{{
+ shift;
++ my $specFuncsRef=shift;
+ my $glob=shift;
+ my %params=@_;
+
+ return IkiWiki::FailReason->new("cannot match destpage") unless exists $params{destpage};
+- if (match_glob($params{destpage}, $glob, @_)) {
++ if (match_glob($params{destpage}, $specFuncsRef, $glob, @_)) {
+ return IkiWiki::SuccessReason->new("destpage matches $glob");
+ }
+ else {
+@@ -111,7 +114,8 @@ sub match_destpage ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_included ($$;@) { #{{{
++sub match_included ($$$;@) { #{{{
++ shift;
+ shift;
+ shift;
+ my %params=@_;
+diff --git a/IkiWiki/Plugin/filecheck.pm b/IkiWiki/Plugin/filecheck.pm
+index 6f71be3..bf472c5 100644
+--- a/IkiWiki/Plugin/filecheck.pm
++++ b/IkiWiki/Plugin/filecheck.pm
+@@ -66,8 +66,9 @@ sub humansize ($) { #{{{
+
+ package IkiWiki::PageSpec;
+
+-sub match_maxsize ($$;@) { #{{{
++sub match_maxsize ($$$;@) { #{{{
+ my $page=shift;
++ shift;
+ my $maxsize=eval{IkiWiki::Plugin::attachment::parsesize(shift)};
+ if ($@) {
+ return IkiWiki::FailReason->new("unable to parse maxsize (or number too large)");
+@@ -87,8 +88,9 @@ sub match_maxsize ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_minsize ($$;@) { #{{{
++sub match_minsize ($$$;@) { #{{{
+ my $page=shift;
++ shift;
+ my $minsize=eval{IkiWiki::Plugin::attachment::parsesize(shift)};
+ if ($@) {
+ return IkiWiki::FailReason->new("unable to parse minsize (or number too large)");
+@@ -108,8 +110,9 @@ sub match_minsize ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_mimetype ($$;@) { #{{{
++sub match_mimetype ($$$;@) { #{{{
+ my $page=shift;
++ shift;
+ my $wanted=shift;
+
+ my %params=@_;
+@@ -138,8 +141,9 @@ sub match_mimetype ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_virusfree ($$;@) { #{{{
++sub match_virusfree ($$$;@) { #{{{
+ my $page=shift;
++ shift;
+ my $wanted=shift;
+
+ my %params=@_;
+@@ -180,7 +184,7 @@ sub match_virusfree ($$;@) { #{{{
+ }
+ } #}}}
+
+-sub match_ispage ($$;@) { #{{{
++sub match_ispage ($$$;@) { #{{{
+ my $filename=shift;
+
+ if (defined IkiWiki::pagetype($filename)) {
+diff --git a/IkiWiki/Plugin/meta.pm b/IkiWiki/Plugin/meta.pm
+index b2c85c8..1ee6a69 100644
+--- a/IkiWiki/Plugin/meta.pm
++++ b/IkiWiki/Plugin/meta.pm
+@@ -264,6 +264,7 @@ sub pagetemplate (@) { #{{{
+ sub match { #{{{
+ my $field=shift;
+ my $page=shift;
++ shift;
+
+ # turn glob into a safe regexp
+ my $re=IkiWiki::glob2re(shift);
+@@ -291,23 +292,23 @@ sub match { #{{{
+
+ package IkiWiki::PageSpec;
+
+-sub match_title ($$;@) { #{{{
++sub match_title ($$$;@) { #{{{
+ IkiWiki::Plugin::meta::match("title", @_);
+ } #}}}
+
+-sub match_author ($$;@) { #{{{
++sub match_author ($$$;@) { #{{{
+ IkiWiki::Plugin::meta::match("author", @_);
+ } #}}}
+
+-sub match_authorurl ($$;@) { #{{{
++sub match_authorurl ($$$;@) { #{{{
+ IkiWiki::Plugin::meta::match("authorurl", @_);
+ } #}}}
+
+-sub match_license ($$;@) { #{{{
++sub match_license ($$$;@) { #{{{
+ IkiWiki::Plugin::meta::match("license", @_);
+ } #}}}
+
+-sub match_copyright ($$;@) { #{{{
++sub match_copyright ($$$;@) { #{{{
+ IkiWiki::Plugin::meta::match("copyright", @_);
+ } #}}}
+