use Perl

• Regexps and T-SQL (Score:1)

  by jplindstrom (594) on 2004.12.19 20:03 (#36941) Journal

  I have two opposing examples of languages that are more likely to need comments than others: regexps and T-SQL (Sybase/SQL Server). One is extremely terse, one is extremely verbose.
  
  Regexps are usually very compact and opaque. Your comment about whitespace is spot on, so /x should obviously be encouraged. But even with a sanely laid out regexp, the pattern of a regexp usually needs comments to indicate exactly what (\w+-\d) means in the context of a program. The regexp syntax itself doesn't allow us to do that. And coming back to a regexp a year later, I find it immensly useful to have a sample line of text of what the regexp is supposed to match.
  
  Stored procedure code in T-SQL on the other hand is ridiculously fluffy. The syntax requires you to express your ideas in so many lines of code that sometimes you need a comment on top of each code block in order to summarize what it does. Kind of what a descriptive method name does in a sane langauge. The verbose syntax actually obscures the meaning of the code because of the low semantic density (wow, new word!).
  
  When it comes to Perl, I find that using implicit $_ often obscures the code. Not using an explicit variable means a missed opportunity to self-document the code by naming the variable properly.
  
  The bad rap Perl gets is probably mostly due to:
  

  • Special variables like $| . If you're not used to reading code with sigils, the special variables will totally throw you.
    
  • Regexps. Which was inherited because they were so useful, but perhaps mostly intended for one-offs in shell script situations.
    
  • The abundance of ugly {} when dereferencing references from sub routine calls.
    

  Reply to This

  • Re: $_ (Score:1)

    by Smylers (2592)

    When it comes to Perl, I find that using implicit $_ often obscures the code. Not using an explicit variable means a missed opportunity to self-document the code by naming the variable properly.

    I think the exact opposite. $_ has a meaning in Perl: “the current ‘thing’ being operated on”. That's a well-defined convention, and it has the advantage of being the same in every program.

    In other languages when people want a temporary variable they often use i or n or s, but they aren'
    • Re: $_ (Score:1)

      by jplindstrom (594)

      Using $i as a loop variable doesn't increase readability unless it is to communicate that "it's just a loop variable" and that's seldom the case since the Perl foreach is so much more useful than the C-style for loop.
      
      If the code block is very brief, like in

      dostuff($_) for(@servers);

      then I agree that it isn't necessary to alias it to a new name. But if the code block is longer than a few lines, it's indeed very useful to have an actual name connected to the entity you're dealing with.
      
      Consider the followi