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Diffstat (limited to 'pod/perlsyn.pod')
| -rw-r--r-- | pod/perlsyn.pod | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod index 8b448505c1..9f964e001f 100644 --- a/pod/perlsyn.pod +++ b/pod/perlsyn.pod @@ -117,7 +117,7 @@ is treated as 0. =head2 Statement Modifiers X<statement modifier> X<modifier> X<if> X<unless> X<while> -X<until> X<foreach> X<for> +X<until> X<when> X<foreach> X<for> Any simple statement may optionally be followed by a I<SINGLE> modifier, just before the terminating semicolon (or block ending). The possible @@ -127,6 +127,8 @@ modifiers are: unless EXPR while EXPR until EXPR + when EXPR + for LIST foreach LIST The C<EXPR> following the modifier is referred to as the "condition". @@ -139,6 +141,22 @@ the condition is true (i.e., if the condition is false). print "Basset hounds got long ears" if length $ear >= 10; go_outside() and play() unless $is_raining; +C<when> executes the statement I<when> C<$_> smart matches C<EXPR>, and +then either C<break>s out if it's enclosed in a C<given> scope or skips +to the C<next> element when it lies directly inside a C<for> loop. +See also L</"Switch statements">. + + given ($something) { + $abc = 1 when /^abc/; + $just_a = 1 when /^a/; + $other = 1; + } + + for (@names) { + admin($_) when [ qw/Alice Bob/ ]; + regular($_) when [ qw/Chris David Ellen/ ]; + } + The C<foreach> modifier is an iterator: it executes the statement once for each item in the LIST (with C<$_> aliased to each item in turn). @@ -738,7 +756,8 @@ underlying structure). The Perl 5 smart match and C<given>/C<when> constructs are not absolutely identical to their Perl 6 analogues. The most visible difference is that, in Perl 5, parentheses are required around -the argument to C<given()> and C<when()>. Parentheses in Perl 6 +the argument to C<given()> and C<when()> (except when this last +one is used as a statement modifier). Parentheses in Perl 6 are always optional in a control construct such as C<if()>, C<while()>, or C<when()>; they can't be made optional in Perl 5 without a great deal of potential confusion, because Perl 5 |