...

Because of precedence/binding

Consider 

$ perl -le " $f = 1,2,3 ; print $f"
1

$ perl -MO=Deparse -le " $f = 1,2,3 ; print $f"
BEGIN { $/ = "\n"; $\ = "\n"; }
$f = 1, '???', '???';
print $f;
-e syntax OK

[download]

Compare it to 

$ perl -le " $f = ( 1,2,3 ); print $f"
3

$ perl -MO=Deparse -le " $f = ( 1,2,3 ) ; print $f"
BEGIN { $/ = "\n"; $\ = "\n"; }
$f = ('???', '???', 3);
print $f;
-e syntax OK

[download]

Since smart is binary (like = in the above example), it works on two scalars, left-scalar operator right-scalar

If you have no parentheses, the first scalar is taken, the closest, because assignment operator (=) has higher precedence than comma opeartor (it binds tighter).

If you add parenthesis, then you have the fabled List in Scalar Context, then the comma operator return the last right item (rightest most)

See Tutorials: Precedence for Idiots

Since you're confused about precedence you're probably also confused about context, so see Tutorials: Context in Perl: Context tutorial, "List" Is a Four-Letter Word, Easy Reference for Contexts

Smart match is giving me a headache...

Stop using it :) worked for me :) Smart-match

In reply to Re^3: ~~ and list literal by Anonymous Monk
in thread ~~ and list literal by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.