I quite regularly write subs that are called only once (e.g. to read a param file and load it into a param hash). Granted, it does not look quite right if you consider that the main point of a sub is to avoid code duplication (the DRY principle), but it is still better IMHO than having hundreds of code lines in the main section of the program. Having a sub to isolate parts of the program that have a well defined purpose is perfectly legitimate in my view, even if called only once (or twice).

Otherwise, if you really want your function to be private, then use an anonymous sub. If not, the leading underscore convention should be sufficient (you can also use caller to check that the sub is called by only another specific function and no other, but that's seems to be overkill in most cases).

In reply to Re: Indent, anonymous sub, or lexical sub for module private code? by Laurent_R
in thread Indent, anonymous sub, or lexical sub for module private code? by 1s44c

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.