Re: 'around' method modifier does not seem to work

--089e0115f83a026bd7051caf0815
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Stupid guess.

You set the attribute successfully then unset it when you fetch it because
you dropped the test for @_ that tells you not to set it then.

On Thursday, August 6, 2015, Marcos Barbeitos <[email protected]> wrote=
:

> Howdy,
>
> I looked up the behavior of the modifier 'around' in <
> http://search.cpan.org/~ether/Moose-2.1600/lib/Moose/Manual/MethodModifie=
rs.pod#Around_modifiers>,
> and the code snipet is:
>
>   around 'size' =3D> sub {
>       my $orig =3D shift;
>       my $self =3D shift;
>
>       return $self->$orig()
>           unless @_;
>
>       my $size =3D shift;
>       $size =3D $size / 2
>           if $self->likes_small_things();
>
>       return $self->$orig($size);
>   };
>
> In my code, I have:
>
> has 'sequence' =3D>
> (
>     is =3D> 'rw'
>   , isa =3D> 'Str'
>   , predicate =3D> 'has_sequence'
> );
>
> around 'sequence' =3D> sub
> {
>     my $orig =3D shift;
>     my $self =3D shift;
>     my $sequence =3D uc shift;
>
>     # Do lots of things with $sequence and then
>
>     return $self->$orig( $sequence );
> }
>
> But the attribute is not set.
>
> I've tried lots of variations of the last line:
>
> $self->$orig( $sequence );
> return $orig->( $self, $sequence );
> $orig->( $self, $sequence );
> return $sequence;
>
> With no success, as expected. However, if I do:
>
> around 'sequence' =3D> sub
> {
>     my $orig =3D shift;
>     my $self =3D shift;
>
>     return $self->$orig( @_ );
> }
>
> The attribute is set and life goes on. Of course, that does not work for
> me because I need to do a bunch of things to the argument passed to this
> method.
>
> Any ideas about the reasons for the (apparent?) discrepancy in behavior?
>
> Best wishes and thanks in advance.
>
> --
> Marcos S. Barbeitos
>
> Departamento de Zoologia - Sala 360
> Setor de Ci=C3=AAncias Biol=C3=B3gicas
> Universidade Federal do Paran=C3=A1
> Caixa Postal 19020
> Curitiba, PR 81531-990
> Brazil
>
> Phone: (55 41) 3361-1634
>

--089e0115f83a026bd7051caf0815
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Stupid guess.<div><br></div><div>You set the attribute successfully then un=
set it when you fetch it because you dropped the test for @_ that tells you=
 not to set it then.<span></span><br><br>On Thursday, August 6, 2015, Marco=
s Barbeitos &lt;<a href=3D"mailto:[email protected]">msbarbeitos@gmail.=
com</a>&gt; wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0=
 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr">Howdy=
,<br><br>I looked up the behavior of the modifier &#39;around&#39; in &lt;<=
a href=3D"http://search.cpan.org/~ether/Moose-2.1600/lib/Moose/Manual/Metho=
dModifiers.pod#Around_modifiers" target=3D"_blank">http://search.cpan.org/~=
ether/Moose-2.1600/lib/Moose/Manual/MethodModifiers.pod#Around_modifiers</a=
>&gt;, and the code snipet is:<br><br>=C2=A0 around &#39;size&#39; =3D&gt; =
sub {<br>=C2=A0 =C2=A0 =C2=A0 my $orig =3D shift;<br>=C2=A0 =C2=A0 =C2=A0 m=
y $self =3D shift;<br><br>=C2=A0 =C2=A0 =C2=A0 return $self-&gt;$orig()<br>=
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 unless @_;<br><br>=C2=A0 =C2=A0 =C2=A0 m=
y $size =3D shift;<br>=C2=A0 =C2=A0 =C2=A0 $size =3D $size / 2<br>=C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 if $self-&gt;likes_small_things();<br><br>=C2=
=A0 =C2=A0 =C2=A0 return $self-&gt;$orig($size);<br>=C2=A0 };<div><br></div=
><div>In my code, I have:</div><div><div><br></div><div>has &#39;sequence&#=
39; =3D&gt;<br></div><div><div>(</div><div>=C2=A0 =C2=A0 is =3D&gt; &#39;rw=
&#39;</div><div>=C2=A0 , isa =3D&gt; &#39;Str&#39;</div><div>=C2=A0 , predi=
cate =3D&gt; &#39;has_sequence&#39;</div><div>);</div></div><div><br></div>=
<div>around &#39;sequence&#39; =3D&gt; sub</div><div>{</div><div>=C2=A0 =C2=
=A0 my $orig =3D shift;</div></div><div><div>=C2=A0 =C2=A0 my $self =3D shi=
ft;</div><div>=C2=A0 =C2=A0 my $sequence =3D uc shift;<br></div><div><br></=
div><div>=C2=A0 =C2=A0 # Do lots of things with $sequence and then</div><di=
v><br></div><div>=C2=A0 =C2=A0 return $self-&gt;$orig( $sequence );<br></di=
v><div>}</div><div><br></div><div>But the attribute is not set.</div><div><=
br></div><div>I&#39;ve tried lots of variations of the last line:</div><div=
><br></div><div>$self-&gt;$orig( $sequence );<br></div><div><div>return $or=
ig-&gt;( $self, $sequence );</div><div>$orig-&gt;( $self, $sequence ); =C2=
=A0 =C2=A0</div><div>return $sequence;</div><div><br></div><div>With no suc=
cess, as expected. However, if I do:</div><div><br></div><div><div><div>aro=
und &#39;sequence&#39; =3D&gt; sub</div><div>{</div><div>=C2=A0 =C2=A0 my $=
orig =3D shift;</div></div><div><div>=C2=A0 =C2=A0 my $self =3D shift;</div=
><div><br></div><div>=C2=A0 =C2=A0 return $self-&gt;$orig( @_ );<br></div><=
div>}</div></div></div><div><br></div><div>The attribute is set and life go=
es on. Of course, that does not work for me because I need to do a bunch of=
 things to the argument passed to this method.</div></div><div><br></div><d=
iv>Any ideas about the reasons for the (apparent?) discrepancy in behavior?=
<br></div><div><br></div><div>Best wishes and thanks in advance.</div><br>-=
-<br>Marcos S. Barbeitos<br><br>Departamento de Zoologia - Sala 360<br>Seto=
r de Ci=C3=AAncias Biol=C3=B3gicas<br>Universidade Federal do Paran=C3=A1<b=
r>Caixa Postal 19020<br>Curitiba, PR 81531-990<br>Brazil<br><br>Phone: (55 =
41) 3361-1634<br><div>
</div></div></div>
</blockquote></div>

--089e0115f83a026bd7051caf0815--