Preliminary patch for a feature wishlist item: [[bugs/pruning_is_too_strict]].

    diff --git a/IkiWiki.pm b/IkiWiki.pm
    index 1a00f2d..7381ae7 100644
    --- a/IkiWiki.pm
    +++ b/IkiWiki.pm
    @@ -20,6 +20,7 @@ our $VERSION = 1.00;
     # Optimisation.
     use Memoize;
     memoize("abs2rel");
    +memoize("is_prune");
     memoize("pagespec_translate");
     
     my $installdir=''; # INSTALLDIR_AUTOREPLACE done by Makefile, DNE
    @@ -331,6 +332,14 @@ sub abs2rel ($$) { #{{{
     	return $ret;
     } #}}}
     
    +sub is_prune ($;$) { #{{{
    +	my $file=shift;
    +	my $base=shift || $config{srcdir};
    +
    +	my $rel=abs2rel($file, $base);
    +	return $rel eq '.' ? 0 : $rel=~m/$config{wiki_file_prune_regexp}/;
    +} #}}}
    +
     sub displaytime ($) { #{{{
     	my $time=shift;
     
    diff --git a/IkiWiki/CGI.pm b/IkiWiki/CGI.pm
    index f550b67..5d1991d 100644
    --- a/IkiWiki/CGI.pm
    +++ b/IkiWiki/CGI.pm
    @@ -386,7 +386,7 @@ sub cgi_editpage ($$) { #{{{
     	my ($page)=$form->field('page');
     	$page=titlepage(possibly_foolish_untaint($page));
     	if (! defined $page || ! length $page ||
    -	    $page=~/$config{wiki_file_prune_regexp}/ || $page=~/^\//) {
    +	    is_prune($page) || $page=~/^\//) {
     		error("bad page name");
     	}
     	
    @@ -476,8 +476,7 @@ sub cgi_editpage ($$) { #{{{
     			my $best_loc;
     			if (! defined $from || ! length $from ||
     			    $from ne $form->field('from') ||
    -			    $from=~/$config{wiki_file_prune_regexp}/ ||
    -			    $from=~/^\// ||
    +			    is_prune($from) || $from=~/^\// ||
     			    $form->submitted eq "Preview") {
     				@page_locs=$best_loc=$page;
     			}
    diff --git a/IkiWiki/Render.pm b/IkiWiki/Render.pm
    index 48a25be..a083d3f 100644
    --- a/IkiWiki/Render.pm
    +++ b/IkiWiki/Render.pm
    @@ -202,7 +202,7 @@ sub refresh () { #{{{
     		no_chdir => 1,
     		wanted => sub {
     			$_=decode_utf8($_);
    -			if (/$config{wiki_file_prune_regexp}/) {
    +			if (is_prune($_)) {
     				$File::Find::prune=1;
     			}
     			elsif (! -d $_ && ! -l $_) {
    @@ -222,7 +222,7 @@ sub refresh () { #{{{
     		no_chdir => 1,
     		wanted => sub {
     			$_=decode_utf8($_);
    -			if (/$config{wiki_file_prune_regexp}/) {
    +			if (is_prune($_, $config{underlaydir})) {
     				$File::Find::prune=1;
     			}
     			elsif (! -d $_ && ! -l $_) {