diff options
Diffstat (limited to 'pod')
| -rw-r--r-- | pod/perl5131delta.pod | 17 | ||||
| -rw-r--r-- | pod/perlsyn.pod | 19 |
2 files changed, 28 insertions, 8 deletions
diff --git a/pod/perl5131delta.pod b/pod/perl5131delta.pod index cfcd3d4a2a..db47d6f17f 100644 --- a/pod/perl5131delta.pod +++ b/pod/perl5131delta.pod @@ -44,6 +44,23 @@ The new local array used to be made tied too, which was fairly pointless, and has now been fixed. This fix could however potentially cause a change in behaviour of some code. +=head2 C<given> return values + +Starting from this release, C<given> blocks returns the last evaluated +expression, or an empty list if the block was exited by C<break>. Thus you +can now write: + + my $type = do { + given ($num) { + break when undef; + 'integer' when /^[+-]?[0-9]+$/; + 'float' when /^[+-]?[0-9]+(?:\.[0-9]+)?$/; + 'unknown'; + } + }; + +See L<perlsyn/Return value> for details. + =head1 Core Enhancements XXX New core language features go here. Summarise user-visible core language diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod index 3a65b4e9d0..29db5dafd5 100644 --- a/pod/perlsyn.pod +++ b/pod/perlsyn.pod @@ -677,28 +677,31 @@ case to the next: =head3 Return value When a C<given> statement is also a valid expression (e.g. -when it's the last statement of a block), it returns : +when it's the last statement of a block), it evaluates to : =over 4 =item * -An empty list as soon as an explicit C<break> is encountered. +an empty list as soon as an explicit C<break> is encountered. =item * -The value of the last evaluated expression of the successful +the value of the last evaluated expression of the successful C<when>/C<default> clause, if there's one. =item * -The value of the last evaluated expression of the C<given> block if no -condition was true. +the value of the last evaluated expression of the C<given> block if no +condition is true. =back -Note that, unlike C<if> and C<unless>, both C<when> and C<default> always -themselves return an empty list. +In both last cases, the last expression is evaluated in the context that +was applied to the C<given> block. + +Note that, unlike C<if> and C<unless>, failed C<when> statements always +evaluate to an empty list. my $price = do { given ($item) { when ([ 'pear', 'apple' ]) { 1 } @@ -707,7 +710,7 @@ themselves return an empty list. 'unknown'; } }; -C<given> blocks can't currently be used as proper expressions. This +Currently, C<given> blocks can't always be used as proper expressions. This may be addressed in a future version of perl. =head3 Switching in a loop |