Gentle Sovixi,

Your pattern matches; good. May I offer some tips?

  1. Use the <code> tags to make your code easier to read. (I see you've updated it to do so; good.)
  2. Your pattern now would match the 1-char string 'N'. Is that really what you want?
  3. You're using capturing parenthesis, but not using the value.
  4. When matching single letters, the square brackets read more easily that the '|' in parens.
  5. Use the 'x' modifier to make your code more readable and commentable. Viz 
if ( $value =~ m/^(?: [AN]+    # Either at least one A|N 
                     |[AN]*     # or an A|N run 
                      (?: NP)?  # Possibly interrupted by NP
                      [AN]* )
                 N$/x ){        # With a terminal N.
 print "match: $value\n"; }

[download]
Something still looks suspicious to me. Your first pattern match is a choice between [AN]+ and [AN]*(NP)?[AN]*. That second choice can match the null string. Seems odd.

throop

In reply to Re^2: matching patterns by throop
in thread matching patterns 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.