NAME

Raku port of Perl's push() / pop() built-ins

SYNOPSIS

use P5push;

my @a = 1,2,3;
say push @a, 42;  # 4

say pop;  # pop from @*ARGS, if any

sub a { dd @_; dd pop; dd @_ }; a 1,2,3;
[1, 2, 3]
3
[1, 2]

DESCRIPTION

This module tries to mimic the behaviour of Perl's push and pop built-ins as closely as possible in the Raku Programming Language.

ORIGINAL PERL 5 DOCUMENTATION

push ARRAY,LIST
push EXPR,LIST
        Treats ARRAY as a stack by appending the values of LIST to the end
        of ARRAY. The length of ARRAY increases by the length of LIST. Has
        the same effect as

            for $value (LIST) {
                $ARRAY[++$#ARRAY] = $value;
            }

        but is more efficient. Returns the number of elements in the array
        following the completed "push".

        Starting with Perl 5.14, "push" can take a scalar EXPR, which must
        hold a reference to an unblessed array. The argument will be
        dereferenced automatically. This aspect of "push" is considered
        highly experimental. The exact behaviour may change in a future
        version of Perl.

        To avoid confusing would-be users of your code who are running
        earlier versions of Perl with mysterious syntax errors, put this
        sort of thing at the top of your file to signal that your code
        will work onlyon Perls of a recent vintage:

            use 5.014;  # so push/pop/etc work on scalars (experimental)

pop ARRAY
pop EXPR
pop     Pops and returns the last value of the array, shortening the array
        by one element.

        Returns the undefined value if the array is empty, although this
        may also happen at other times. If ARRAY is omitted, pops the
        @ARGV array in the main program, but the @_ array in subroutines,
        just like "shift".

        Starting with Perl 5.14, "pop" can take a scalar EXPR, which must
        hold a reference to an unblessed array. The argument will be
        dereferenced automatically. This aspect of "pop" is considered
        highly experimental. The exact behaviour may change in a future
        version of Perl.

        To avoid confusing would-be users of your code who are running
        earlier versions of Perl with mysterious syntax errors, put this
        sort of thing at the top of your file to signal that your code
        will work only on Perls of a recent vintage:

            use 5.014;  # so push/pop/etc work on scalars (experimental)

PORTING CAVEATS

In future language versions of Raku, it will become impossible to access the @_ variable of the caller's scope, because it will not have been marked as a dynamic variable. So please consider changing:

pop;

to:

pop(@_);

or, using the subroutine as a method syntax:

@_.&pop;

AUTHOR

Elizabeth Mattijsen [email protected]

Source can be located at: https://github.com/lizmat/P5push . Comments and Pull Requests are welcome.

COPYRIGHT AND LICENSE

Copyright 2018, 2019, 2020, 2021 Elizabeth Mattijsen

Re-imagined from Perl as part of the CPAN Butterfly Plan.

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.