.\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.40) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Data::Swap 3pm" .TH Data::Swap 3pm "2020-11-08" "perl v5.32.0" "User Contributed Perl Documentation" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Data::Swap \- Swap type and contents of variables .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& use Data::Swap; \& \& my $p = []; \& my $q = {}; \& print "$p $q\en"; # ARRAY(0x965cc) HASH(0x966b0) \& swap $p, $q; # swap referenced variables \& print "$p $q\en"; # HASH(0x965cc) ARRAY(0x966b0) \& \& my $x = {}; \& my $y = $x; # $x and $y reference same var \& swap $x, [1, 2, 3]; # swap referenced var with an array \& print "@$y\en"; # 1 2 3 \& \& use Data::Swap \*(Aqderef\*(Aq; \& \& my @refs = (\e$x, \e@y); \& $_++ for deref @refs; # dereference a list of references \& \& # Note that I omitted \e%z from the @refs because $_++ would fail \& # on a key, but deref does work on hash\-refs too of course. .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" This module allows you to swap the contents of two referenced variables, even if they have different types. .PP The main application is to change the base type of an object after it has been created, for example for dynamic loading of data structures: .PP .Vb 1 \& swap $self, bless $replacement, $newclass; .Ve .PP This module additionally contain the function \f(CW\*(C`deref\*(C'\fR which acts like a generic list-dereferencing operator. .SH "FUNCTIONS" .IX Header "FUNCTIONS" .SS "swap \fI\s-1REF1\s0\fP, \fI\s-1REF2\s0\fP" .IX Subsection "swap REF1, REF2" Swaps the contents (and if necessary, type) of two referenced variables. .SS "deref \fI\s-1LIST\s0\fP" .IX Subsection "deref LIST" Dereferences a list of scalar refs, array refs and hash refs. Mainly exists because you can't use \f(CW\*(C`map\*(C'\fR for this application, as it makes copies of the dereferenced values. .SH "KNOWN ISSUES" .IX Header "KNOWN ISSUES" You can't \f(CW\*(C`swap\*(C'\fR an overloaded object with a non-overloaded one, unless you use Perl 5.10 or later. .PP Also, don't use \f(CW\*(C`swap\*(C'\fR to change the type of a directly accessible variable \*(-- like \f(CW\*(C`swap \e$x, \e@y\*(C'\fR. That's just asking for segfaults. Unfortunately there is no good way for me to detect and prevent this. .SH "AUTHOR" .IX Header "AUTHOR" Matthijs van Duin .PP Copyright (C) 2003, 2004, 2007, 2008 Matthijs van Duin. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.