.\" Automatically generated by Pod::Man 4.10 (Pod::Simple 3.35) .\" .\" 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 .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "MooseX::UndefTolerant 3pm" .TH MooseX::UndefTolerant 3pm "2019-02-20" "perl v5.28.1" "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" MooseX::UndefTolerant \- Make your attribute(s) tolerant to undef initialization .SH "VERSION" .IX Header "VERSION" version 0.21 .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& package My::Class; \& \& use Moose; \& use MooseX::UndefTolerant; \& \& has \*(Aqname\*(Aq => ( \& is => \*(Aqro\*(Aq, \& isa => \*(AqStr\*(Aq, \& predicate => \*(Aqhas_name\*(Aq \& ); \& \& # Meanwhile, under the city... \& \& # Doesn\*(Aqt explode \& my $class = My::Class\->new(name => undef); \& $class\->has_name # False! .Ve .PP Or, if you only want one attribute to have this behaviour: .PP .Vb 2 \& package My:Class; \& use Moose; \& \& use MooseX::UndefTolerant::Attribute; \& \& has \*(Aqbar\*(Aq => ( \& traits => [ qw(MooseX::UndefTolerant::Attribute)], \& is => \*(Aqro\*(Aq, \& isa => \*(AqNum\*(Aq, \& predicate => \*(Aqhas_bar\*(Aq \& ); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" Loading this module in your Moose class makes initialization of your attributes tolerant of undef. If you specify the value of undef to any of the attributes they will not be initialized, effectively behaving as if you had not provided a value at all. .PP You can also apply the 'UndefTolerant' trait to individual attributes. See MooseX::UndefTolerant::Attribute for details. .PP There will be no change in behaviour to any attribute with a type constraint that accepts undef values (for example \f(CW\*(C`Maybe\*(C'\fR types), as it is presumed that since the type is already \*(L"undef tolerant\*(R", there is no need to avoid initializing the attribute value with \f(CW\*(C`undef\*(C'\fR. .PP As of Moose 1.9900, this module can also be used in a role, in which case all of that role's attributes will be undef-tolerant. .SH "MOTIVATION" .IX Header "MOTIVATION" I often found myself in this quandary: .PP .Vb 2 \& package My:Class; \& use Moose; \& \& has \*(Aqfoo\*(Aq => ( \& is => \*(Aqro\*(Aq, \& isa => \*(AqStr\*(Aq, \& ); \& \& # ... then \& \& my $foo = ... # get the param from something \& \& my $class = My:Class\->new(foo => $foo, bar => 123); .Ve .PP What if foo is undefined? I didn't want to change my attribute to be Maybe[Str] and I still want my predicate (\f(CW\*(C`has_foo\*(C'\fR) to work. The only real solution was: .PP .Vb 5 \& if(defined($foo)) { \& $class = My:Class\->new(foo => $foo, bar => 123); \& } else { \& $class = My:Class\->new(bar => 123); \& } .Ve .PP Or some type of codemulch using ternary conditionals. This module allows you to make your attributes more tolerant of undef so that you can keep the first example: have your cake and eat it too! .SH "PER ATTRIBUTE" .IX Header "PER ATTRIBUTE" See MooseX::UndefTolerant::Attribute. .SH "CAVEATS" .IX Header "CAVEATS" This extension does not currently work in immutable classes when applying the trait to some (but not all) attributes in the class. This is because the inlined constructor initialization code currently lives in Moose::Meta::Class, not Moose::Meta::Attribute. The good news is that this is expected to be changing shortly. .SH "ACKNOWLEDGEMENTS" .IX Header "ACKNOWLEDGEMENTS" Many thanks to the crew in #moose who talked me through this module: .Sp .RS 4 Hans Dieter Pearcey (confound) Jesse Luehrs (doy) Tomas Doran (t0m) Dylan Hardison (dylan) Jay Shirley (jshirley) Mike Eldridge (diz) .RE .SH "SUPPORT" .IX Header "SUPPORT" Bugs may be submitted through the \s-1RT\s0 bug tracker (or bug\-MooseX\-UndefTolerant@rt.cpan.org ). .PP There is also a mailing list available for users of this distribution, at . .PP There is also an irc channel available for users of this distribution, at \&\f(CW\*(C`#moose\*(C'\fR on \f(CW\*(C`irc.perl.org\*(C'\fR . .SH "AUTHOR" .IX Header "AUTHOR" Cory G Watson .SH "CONTRIBUTORS" .IX Header "CONTRIBUTORS" .IP "\(bu" 4 Karen Etheridge .IP "\(bu" 4 Dave Rolsky .IP "\(bu" 4 Cory G Watson .IP "\(bu" 4 Jesse Luehrs .IP "\(bu" 4 Chris Andrews .SH "COPYRIGHT AND LICENSE" .IX Header "COPYRIGHT AND LICENSE" This software is copyright (c) 2011 by Cory G Watson. .PP This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.