Merge branch 'master' of ssh://ikiwiki.branchable.com

[ikiwiki.git] / IkiWiki.pm

diff --git a/IkiWiki.pm b/IkiWiki.pm
index 49ac9719658496953dc5f32c920e27ee5ba9d20c..4ad365c1d90991e9098ea2439c231b46d4c43ee1 100644 (file)
--- a/IkiWiki.pm
+++ b/IkiWiki.pm
@@ -2578,21 +2578,48 @@ our @ISA = 'IkiWiki::SuccessReason';
 
 package IkiWiki::SuccessReason;
 
+# A blessed array-ref:
+#
+# [0]: human-readable reason for success (or, in FailReason subclass, failure)
+# [1]{""}:
+#      - if absent or false, the influences of this evaluation are "static",
+#        see the influences_static method
+#      - if true, they are dynamic (not static)
+# [1]{any other key}:
+#      the dependency types of influences, as returned by the influences method
+
 use overload (
+       # in string context, it's the human-readable reason
        '""'    => sub { $_[0][0] },
+       # in boolean context, SuccessReason is 1 and FailReason is 0
        '0+'    => sub { 1 },
+       # negating a result gives the opposite result with the same influences
        '!'     => sub { bless $_[0], 'IkiWiki::FailReason'},
+       # A & B = (A ? B : A) with the influences of both
        '&'     => sub { $_[1]->merge_influences($_[0], 1); $_[1] },
+       # A | B = (A ? A : B) with the influences of both
        '|'     => sub { $_[0]->merge_influences($_[1]); $_[0] },
        fallback => 1,
 );
 
+# SuccessReason->new("human-readable reason", page => deptype, ...)
+
 sub new {
        my $class = shift;
        my $value = shift;
        return bless [$value, {@_}], $class;
 }
 
+# influences(): return a reference to a copy of the hash
+# { page => dependency type } describing the pages that indirectly influenced
+# this result, but would not cause a dependency through ikiwiki's core
+# dependency logic.
+#
+# See [[todo/dependency_types]] for extensive discussion of what this means.
+#
+# influences(page => deptype, ...): remove all influences, replace them
+# with the arguments, and return a reference to a copy of the new influences.
+
 sub influences {
        my $this=shift;
        $this->[1]={@_} if @_;
@@ -2601,15 +2628,46 @@ sub influences {
        return \%i;
 }
 
+# True if this result has the same influences whichever page it matches,
+# For instance, whether bar matches backlink(foo) is influenced only by
+# the set of links in foo, so its only influence is { foo => DEPEND_LINKS },
+# which does not mention bar anywhere.
+#
+# False if this result would have different influences when matching
+# different pages. For instance, when testing whether link(foo) matches bar,
+# { bar => DEPEND_LINKS } is an influence on that result, because changing
+# bar's links could change the outcome; so its influences are not the same
+# as when testing whether link(foo) matches baz.
+#
+# Static influences are one of the things that make pagespec_match_list
+# more efficient than repeated calls to pagespec_match.
+
 sub influences_static {
        return ! $_[0][1]->{""};
 }
 
+# Change the influences of $this to be the influences of "$this & $other"
+# or "$this | $other".
+#
+# If both $this and $other are either successful or have influences,
+# or this is an "or" operation, the result has all the influences from
+# either of the arguments. It has dynamic influences if either argument
+# has dynamic influences.
+#
+# If this is an "and" operation, and at least one argument is a
+# FailReason with no influences, the result has no influences, and they
+# are not dynamic. For instance, link(foo) matching bar is influenced
+# by bar, but enabled(ddate) has no influences. Suppose ddate is disabled;
+# then (link(foo) and enabled(ddate)) not matching bar is not influenced by
+# bar, because it would be false however often you edit bar.
+
 sub merge_influences {
        my $this=shift;
        my $other=shift;
        my $anded=shift;
 
+       # This "if" is odd because it needs to avoid negating $this
+       # or $other, which would alter the objects in-place. Be careful.
        if (! $anded || (($this || %{$this->[1]}) &&
                         ($other || %{$other->[1]}))) {
                foreach my $influence (keys %{$other->[1]}) {
@@ -2622,6 +2680,8 @@ sub merge_influences {
        }
 }
 
+# Change $this so it is not considered to be influenced by $torm.
+
 sub remove_influence {
        my $this=shift;
        my $torm=shift;