Raku port of Perl's length() built-in
use P5length; # exports length()
say length("foobar"); # 6
say length(Str); # Str
$_ = "foobar";
say length; # 6
This module tries to mimic the behaviour of Perl's
length built-in as closely as possible in the Raku Programming Language.
ORIGINAL PERL 5 DOCUMENTATION
length Returns the length in characters of the value of EXPR. If EXPR is
omitted, returns the length of $_. If EXPR is undefined, returns
This function cannot be used on an entire array or hash to find
out how many elements these have. For that, use "scalar @array"
and "scalar keys %hash", respectively.
Like all Perl character operations, length() normally deals in
logical characters, not physical bytes. For how many bytes a
string encoded as UTF-8 would take up, use
"length(Encode::encode_utf8(EXPR))" (you'll have to "use Encode"
first). See Encode and perlunicode.
Characters vs codepoints
Since the Perl documentation mentions
characters rather than codepoints,
length will return the number of characters, as seen using Normalization Form Grapheme (NFG).
Handling of type objects
length in Perl is supposed to return
undef when given
undef. Since undefined values are type objects in Raku, and it looks like
length is simply returning what it was given in the undefined case, it felt appropriate to simply return the given type object rather than
$_ no longer accessible from caller's scope
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:
or, using the subroutine as a method syntax, with the prefix
. shortcut to use that scope's
$_ as the invocant:
Elizabeth Mattijsen email@example.com
Source can be located at: https://github.com/lizmat/P5length . Comments and Pull Requests are welcome.
COPYRIGHT AND LICENSE
Copyright 2018-2020 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.