Is it a bug that perl produces no warnings in this case?

"." is the concatenation operator, and you used it properly. There's no reason for it to give a warning.

As for a hash element index, it accepts multiple comma-separated values. This was a means of doing multilevel hashes before Perl had true references. These days, one would create a hash or hashes. 

$hash{A}{B} = 1;
$hash{C}{D} = 2;
$hash{E}{F} = 3;

[download]

Again, it was used properly, so there's no reason for it give a warning.

Why is it '1c' and not 'f5'?

F5? As in LATIN SMALL LETTER O WITH TILDE? Why do you expect that?

It can be done, though. Just change $; to "\xF5".

In reply to Re: Comma Operator, BUG or feature ??? by ikegami
in thread Comma Operator, BUG or feature ??? by nif

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.