Re: perldiag.pod entry for "Scalar value @%s{%s} ..."

On Mon, 30 Dec 1996 21:28:30 -0500, Gurusamy Sarathy <gsar@engin.umich.edu> said:
> On Mon, 30 Dec 1996 21:09:12 EST, Roderick Schertler wrote:
>>
>> +=item Scalar value @%s{%s} better written as $%s{%s}
>> +
>> +This is just like the previous entry, but for hashes instead of arrays.
>> +
>
> Won't that look odd under -Mdiagnostics?  Better to spell it out
> again.

Right you are.  This diff goes on top of the one above.

p5p-msgid: <2043.852051019@eeyore.ibcinc.com>

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 49d30fc..780aefc 100644 (file)
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -1815,7 +1815,7 @@ shifting or popping (for array variables).  See L<perlform>.
 
 =item Scalar value @%s[%s] better written as $%s[%s]
 
-(W) You've used an array slice (indicated by @) to select a single value of
+(W) You've used an array slice (indicated by @) to select a single element of
 an array.  Generally it's better to ask for a scalar value (indicated by $).
 The difference is that C<$foo[&bar]> always behaves like a scalar, both when
 assigning to it and when evaluating its argument, while C<@foo[&bar]> behaves
@@ -1827,6 +1827,20 @@ element as a list, you need to look into how references work, because
 Perl will not magically convert between scalars and lists for you.  See
 L<perlref>.
 
+=item Scalar value @%s{%s} better written as $%s{%s}
+
+(W) You've used a slice (indicated by @) to select a single element of
+a hash.  Generally it's better to ask for a scalar value (indicated by $).
+The difference is that C<$foo{&bar}> always behaves like a scalar, both when
+assigning to it and when evaluating its argument, while C<@foo{&bar}> behaves
+like a list when you assign to it, and provides a list context to its
+subscript, which can do weird things if you're expecting only one subscript.
+
+On the other hand, if you were actually hoping to treat the hash
+element as a list, you need to look into how references work, because
+Perl will not magically convert between scalars and lists for you.  See
+L<perlref>.
+
 =item Script is not setuid/setgid in suidperl
 
 (F) Oddly, the suidperl program was invoked on a script with its setuid