Rules / Types, classes & roles / basic

Label Reference

Tagged location in the source code

What it is #

Routines #

Signatures are reproduced from the documentation, including their declared return types. A routine listed here is part of the type's published interface; whether Raku++ implements it is a separate question, answered by the examples below.

method name #

Not terribly useful, returns the name of the defined label:

method file #

Returns the file the label is defined in.

method line #

Returns the line where the label has been defined.

method Str #

Converts to a string including the name, file and line it's been defined in.

method next #

method next(Label:)

Begin the next iteration of the loop associated with the label.

method redo #

method redo(Label:)

Repeat the same iteration of the loop associated with the label.

method last #

method last(Label:)

Terminate the execution of the loop associated with the label.

Examples, run three ways #

Every example below comes from the official documentation, together with the output that documentation asserts. Each was then executed by Rakudo and by Raku++ when this page was built. Where the three agree, one result is shown; where they do not, all three are — because which of them is wrong is exactly the information worth having.

3 doc-drift · 5 no-output · 3 ok · 1 unrun

class Label {}

Not executed: the documentation states no expected output for this example.

USERS:          # the label
for @users -> $u {
for $u.pets -> $pet {
    # usage of a label
    next USERS if $pet.barks;
}
say "None of {$u}'s pets barks";
}
say USERS.^name;        # OUTPUT: «Label␤»
my $x = 0;
my $y = 0;
my $t = '';
A: while $x++ < 2 {
$t ~= "A$x";
B: while $y++ < 2 {
    $t ~= "B$y";
    redo A if $y++ == 1;
    last A
}
}
say $t; # OUTPUT: «A1B1A1A2␤»
Output
A1B1A1A2

Documentation, Rakudo and Raku++ all agree.

駱駝道: while True {
  say 駱駝道.name;
  last 駱駝道;
}  # OUTPUT: «駱駝道␤»
Output
駱駝道

Documentation, Rakudo and Raku++ all agree.

A: while True {
  say A.name; # OUTPUT: «A␤»
  last A;
}
Output
A

Documentation, Rakudo and Raku++ all agree.

MY-LABEL:
for 1..10 {
    next MY-LABEL if $_ < 5;
    print "$_ ";
}

Not executed: the documentation states no expected output for this example.

# OUTPUT: «5 6 7 8 9 10 »
Documentation
5 6 7 8 9 10
Rakudo
Raku++

Both engines agree; the documentation states something else. Trust the engines.

my $has-repeated = False;

Not executed: the documentation states no expected output for this example.

MY-LABEL:
for 1..10 {
    print "$_ ";
    if $_ == 5 {
        LEAVE $has-repeated = True;
        redo MY-LABEL unless $has-repeated;
    }
}

Not executed: the documentation states no expected output for this example.

# OUTPUT: «1 2 3 4 5 5 6 7 8 9 10 »
Documentation
1 2 3 4 5 5 6 7 8 9 10
Rakudo
Raku++

Both engines agree; the documentation states something else. Trust the engines.

MY-LABEL:
for 1..10 {
    last MY-LABEL if $_ > 5;
    print "$_ ";
}

Not executed: the documentation states no expected output for this example.

# OUTPUT: «1 2 3 4 5 »
Documentation
1 2 3 4 5
Rakudo
Raku++

Both engines agree; the documentation states something else. Trust the engines.