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Ruby - standard operators are overloaded. Perl - they are not

Liverpool - near Pier HeadRuby has been described to me as "What Perl 5.5 should have been", but that statement is a severe dis-service to Ruby, and to Perl. Ruby is a new language, and if you're moving into Ruby from Perl, you'll do best not to assume even the basics from Perl. A lot has been learend from Perl, for sure, but that does not mean it has been copied. And the differences start with the fact that in Ruby, everything is an object. With Ruby that goes further too; opearators are really just methods running on the object that's to their left.

Let's see an example in Ruby:

  print "How warm is it today (C) "
  results = gets
  val1 = results.to_i * 9
  val2 = results * 9
  val3 = results.to_f * 9
  puts val1
  puts val2
  puts val3


result:

  munchkin:lruby grahamellis$ ruby nother
  How warm is is today (C) 34
  306
  34
  34
  34
  34
  34
  34
  34
  34
  34
  306.0
  etc


The multiplication method differs ... in Ruby, if I multiply an integer by an integer, I get an integer result. If I multiply a floating point number by an integer, I get a floating point result. And if I multiply a string by an integer, I duplicate that string the number of times given by the integer.

In Perl, the * operator is always numeric and the data is silently converted from a string if necessary, and the x operator provides string replication - converting a number into a string ahead of time if it needs to do so.

The code used above is included in a complete example from the private Ruby Programming Course which I ran last week in Liverpool. Full example source [here]. Picture accompanyng article also from Liverpool - sort of appropriate as I've been examining code in detail in this article.

(written 2012-06-09, updated 2012-06-16)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
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  [987] Ruby v Perl - interpollating variables - (2006-12-15)
  [970] String duplication - x in Perl, * in Python and Ruby - (2006-12-07)


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