=begin pod

=head1 NAME

Raku port of Perl's chomp() / chop() built-ins

=head1 SYNOPSIS

=begin code :lang<raku>
use P5chomp; # exports chomp() and chop()

chomp $a;
chomp @a;
chomp %h;
chomp($a,$b);

chop $a;
chop @a;
chop %h;
chop($a,$b);
=end code

=head1 DESCRIPTION

This module tries to mimic the behaviour of the Perl's C<chomp> and C<chop>
built-ins in Raku as closely as possible.

=head1 ORIGINAL PERL 5 DOCUMENTATION

=begin output
chop VARIABLE
chop( LIST )
chop    Chops off the last character of a string and returns the character
        chopped. It is much more efficient than "s/.$//s" because it
        neither scans nor copies the string. If VARIABLE is omitted, chops
        $_. If VARIABLE is a hash, it chops the hash's values, but not its
        keys, resetting the "each" iterator in the process.

        You can actually chop anything that's an lvalue, including an
        assignment.

        If you chop a list, each element is chopped. Only the value of the
        last "chop" is returned.

        Note that "chop" returns the last character. To return all but the
        last character, use "substr($string, 0, -1)".

chomp VARIABLE
chomp( LIST )
chomp   This safer version of "chop" removes any trailing string that
        corresponds to the current value of $/ (also known as
        $INPUT_RECORD_SEPARATOR in the "English" module). It returns the
        total number of characters removed from all its arguments. It's
        often used to remove the newline from the end of an input record
        when you're worried that the final record may be missing its
        newline. When in paragraph mode ("$/ = """), it removes all
        trailing newlines from the string. When in slurp mode ("$/ =
        undef") or fixed-length record mode ($/ is a reference to an
        integer or the like; see perlvar) chomp() won't remove anything.
        If VARIABLE is omitted, it chomps $_. Example:

            while (<>) {
                chomp;  # avoid \n on last field
                @array = split(/:/);
                # ...
            }

        If VARIABLE is a hash, it chomps the hash's values, but not its
        keys, resetting the "each" iterator in the process.

        You can actually chomp anything that's an lvalue, including an
        assignment:

            chomp($cwd = `pwd`);
            chomp($answer = <STDIN>);

        If you chomp a list, each element is chomped, and the total number
        of characters removed is returned.

        Note that parentheses are necessary when you're chomping anything
            that is not a simple variable. This is because "chomp $cwd =
            `pwd`;" is interpreted as "(chomp $cwd) = `pwd`;", rather than as
            "chomp( $cwd = `pwd` )" which you might expect. Similarly, "chomp
            $a, $b" is interpreted as "chomp($a), $b" rather than as
            "chomp($a, $b)".
=end output

=head1 PORTING CAVEATS

Note that there are subtle differences in the semantics of C<chomp> and
C<chop> between Raku and Perl.

In Perl, C<chomp> and C<chop> alter the variables specified, and return
what has been chomped or chopped.  In Raku they do not: they just return
a value that has been chomped or chopped (more functional programming
like).  Also, in Raku the argument specified with C<chop> is interpreted
as the number of characters to be removed from the end.

With the arrival of RakuAST, it has become impossible to access the
topic variable (C<$_>) of the caller's scope.  So Perl's idiom of
calling C<chop> or C<chomp> has become impossible.  Code such as:

=begin code :lang<raku>
chomp;
=end code

should be changed to either:

=begin code :lang<raku>
chomp($_);
=end code

or, using the subroutine as a method syntax, with the prefix C<.> shortcut
to use that scope's C<$_> as the invocant:

=begin code :lang<raku>
.&chomp;
=end code

=head1 AUTHOR

Elizabeth Mattijsen <liz@raku.rocks>

Source can be located at: https://github.com/lizmat/P5chomp . Comments and
Pull Requests are welcome.

If you like this module, or what I'm doing more generally, committing to a
L<small sponsorship|https://github.com/sponsors/lizmat/>  would mean a great
deal to me!

=head1 COPYRIGHT AND LICENSE

Copyright 2018, 2019, 2020, 2021, 2026 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.

=end pod

# vim: expandtab shiftwidth=4
