I don't know when it was introduced, but it was before 5.6

You're right. I was fooled by a funny, little quirk: 

$ perl555 -e 'use 5.006' 
syntax error at -e line 1, at EOF
Execution of -e aborted due to compilation errors.

$ perl555 -e 'use 5.006;'
Perl 5.006 required--this is only version 5.00505, stopped at -e line 
+1.
BEGIN failed--compilation aborted at -e line 1.

[download]

Apparently the semicolon is significant.

So, the broader point still holds not to use dotted-numerics, even with a semicolon:

$ perl555 -e 'use 5.6.0;'
syntax error at -e line 1, near "use 5.6"
Execution of -e aborted due to compilation errors.

[download]
Isn't the syntax deprecated or invalid in future versions too?

I think you're referring to "v-strings" -- v5.6.0 -- whereas this is some magic in parsing use with ordinary 5.6.0 as some sort of bareword. E.g. (and without the semicolon)

$ perl562 -e 'use v5.8.0'
Perl v5.8.0 required--this is only v5.6.2, stopped at -e line 1.
BEGIN failed--compilation aborted at -e line 1.

$ perl562 -e 'use 5.8.0'
Perl v5.8.0 required--this is only v5.6.2, stopped at -e line 1.
BEGIN failed--compilation aborted at -e line 1.

[download]

I don't know if the latter is going away or not.

-xdg

Code written by xdg and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.

In reply to Re^2: Don't use 5.6.N by xdg
in thread Don't use 5.6.N by xdg

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.