Rules / Types, classes & roles / composite

Slip Reference

A kind of List that automatically flattens into an outer container

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 List #

multi method List(Slip:D: --> List:D)

Returns List:D.

Turns it into a list.

sub slip #

multi slip(--> Empty)
multi slip(@args --> Slip:D)
multi slip(+args --> Slip:D)

Returns Empty or Slip:D.

Creates a Slip from its arguments by calling .Slip on the object formed by them. Returns Empty if called with void arguments.

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.

4 no-output · 3 ok · 1 rakupp-differs

class Slip is List {}

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

say <a b c>.map({ ($_, $_.uc).Slip }).join('|');        # OUTPUT: «a|A|b|B|c|C␤»
Output
a|A|b|B|c|C

Documentation, Rakudo and Raku++ all agree.

say <a b c>.map({ $_, $_.uc }).join('|');               # OUTPUT: «a A|b B|c C␤»
Output
a A|b B|c C

Documentation, Rakudo and Raku++ all agree.

# This says "1" and then says "2", rather than saying "(1 2)"
.say for gather {
    take slip(1, 2);
}

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

my $l = (1, 2, 3);
say (1, slip 2, 3).raku;  # says (1, 2, 3)          , slips 2, 3 into (1, …)
say (0, slip $l, 4).raku; # says (0, $(1, 2, 3), 4) , $l does not break apart
say (0, slip $l).raku;    # says (0, 1, 2, 3)       , slips from $l into (0, …)
say (0, $l.Slip).raku;    # says (0, 1, 2, 3)       , slips from $l into (0, …)
say (0, $l.Slip, 4).raku; # says (0, 1, 2, 3, 4)    , slips from $l into (0, …, 4)
say (|$l).raku;           # says slip(1, 2, 3)      , breaks apart $l
say (0, (|$l, 4), 5);     # says (0 (1 2 3 4) 5)    , slips from $l into (…, 4)
say (0, ($l.Slip, 4), 5); # says (0 (1 2 3 4) 5)    , slips from $l into (…, 4)
say (0, (slip $l, 4), 5); # says (0 (1 2 3) 4 5)    , slips ($l, 4) into (0, …, 5)
say (0, ($l, 4).Slip, 5); # says (0 (1 2 3) 4 5)    , slips ($l, 4) into (0, …, 5)

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

my \l = gather for 1..10 -> $a, $b { take |($a, $b) }; say l.raku;
# OUTPUT: «((1, 2), (3, 4), (5, 6), (7, 8), (9, 10)).Seq␤»
my \m= gather for 1..10 -> $a, $b { take ($a, $b).Slip }; say m.raku;
# OUTPUT: «(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).Seq␤»
Documentation
((1, 2), (3, 4), (5, 6), (7, 8), (9, 10)).Seq
(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).Seq
Rakudo
((1, 2), (3, 4), (5, 6), (7, 8), (9, 10)).Seq
(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).Seq
Raku++
$(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).Seq
$((1, 2), (3, 4), (5, 6), (7, 8), (9, 10)).Seq

Raku++ disagrees with both the documentation and Rakudo — a defect.

say "".comb ~~ Empty;
# OUTPUT: «True␤»
Output
True

Documentation, Rakudo and Raku++ all agree.

do if 0 {};
(42 if 0);
do with Any {};
(42 with Any);

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