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authorChip Salzenberg <chip@pobox.com>2009-08-20 11:48:25 -0700
committerChip Salzenberg <chip@pobox.com>2009-08-20 11:48:25 -0700
commitb7b3ac231a23ed1cc1b90a1ade1bad9fe28d847e (patch)
treec6f7c061ec7aadf08672da79734d7b15dfbeb1e1
parent258cccad0bdc457934bddf4949238caef4203e8e (diff)
downloadperl-b7b3ac231a23ed1cc1b90a1ade1bad9fe28d847e.tar.gz
improve smart match documentation, per DM
-rw-r--r--lib/overload.pm5
-rw-r--r--pod/perlsyn.pod17
2 files changed, 11 insertions, 11 deletions
diff --git a/lib/overload.pm b/lib/overload.pm
index b48cae2ce7..0cb4771845 100644
--- a/lib/overload.pm
+++ b/lib/overload.pm
@@ -423,8 +423,9 @@ once and with scalar context.
=item * I<Matching>
-The key C<"~~"> allows you to override the smart matching used by
-the switch construct. See L<feature>.
+The key C<"~~"> allows you to override the smart matching logic used by
+the C<~~> operator and the switch construct (C<given>/C<when>). See
+L<perlsyn/switch> and L<feature>.
=item * I<Dereferencing>
diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod
index 147844a137..2a83a1c4d2 100644
--- a/pod/perlsyn.pod
+++ b/pod/perlsyn.pod
@@ -550,8 +550,10 @@ is exactly equivalent to
when($_ ~~ $foo)
-In fact C<when(EXPR)> is treated as an implicit smart match most of the
-time. The exceptions are that when EXPR is:
+Most of the time, C<when(EXPR)> is treated as an implicit smart match of
+C<$_>, i.e. C<$_ ~~ EXPR>. (See L</"Smart matching in detail"> for more
+information on smart matching.) But when EXPR is one of the below
+exceptional cases, it is used directly as a boolean:
=over 4
@@ -622,9 +624,6 @@ for example.
C<default> behaves exactly like C<when(1 == 1)>, which is
to say that it always matches.
-See L</"Smart matching in detail"> for more information
-on smart matching.
-
=head3 Breaking out
You can use the C<break> keyword to break out of the enclosing
@@ -672,6 +671,10 @@ implicitly dereferences any non-blessed hash or array ref, so the "Hash"
and "Array" entries apply in those cases. (For blessed references, the
"Object" entries apply.)
+Note that the "Matching Code" column is not always an exact rendition. For
+example, the smart match operator short-circuits whenever possible, but
+C<grep> does not.
+
$a $b Type of Match Implied Matching Code
====== ===== ===================== =============
Any undef undefined !defined $a
@@ -711,10 +714,6 @@ and "Array" entries apply in those cases. (For blessed references, the
3 - If a circular reference is found, we fall back to referential equality.
4 - either a real number, or a string that looks like a number
-The "matching code" doesn't represent the I<real> matching code,
-of course: it's just there to explain the intended meaning. Unlike
-C<grep>, the smart match operator will short-circuit whenever it can.
-
=head3 Custom matching via overloading
You can change the way that an object is matched by overloading