I was answering a question posted to one of the myriad of Perl mailing lists a few moments ago, and was reminded of this interesting point.

We're all told (or do the telling of) "use strict always!" and "barewords are bad". But the motivation for why barewords are bad might not be clear.

Back in the Perl3 days, when barewords were added, I came up with this interesting little puzzle. See if you can solve it. Don't post your answers without hiding them somehow (readmore, black-on-black, or some other way).

The Puzzle

Presuming no "use strict" (or the days of Perl3), why does:

@days = (sun,mon,tue,wed,thu,fri,sat);
[download]

work OK, but

@months = (jan,feb,mar,apr,may,jun,jul,aug,sep,oct,nov,dec);
[download]

fail?

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.