Expanding and compressing in Ruby Method calls

One of the things I didn't like in Ruby at all is the support for method overloading. You have no ways to support it in a straight forward way other than to define a single method that takes a variable number of arguments.

def foo(*f)
  f.each { |a| 
    puts a
  }
end

foo("Hello", "world")

What the above does is that it converts the multiple parameters into a single array and passes it to the method call. I think this is really bad because method overloading is a very basic requirement.

However, Ruby seemed to support another really weird feature of expanding arrays in method calls. What this means is that if a method accepts a number of parameters and it's called with an array then the array is expanded such that the i'th element in the array is passed as the i'th argument.

def bar(name, address, age)
  puts (name, address, age)
end

details = ["Abhinaba", "Hyderabad, India", 42]
bar(*details)

So details[0] is passed to the name parameter and details[1] is passed as address, and so on

Bar Charts on the console

I work on the UI action recorder and it has a strict performance requirement. The tool dumps the time it takes to record each action in it's log and that is compared against the maximum allowed value (otherwise the system will seem sluggish). To do this obviously we need fancy charts, as everyone likes them, other than of course the alpha-geeks :).

However, I like the console chart. Way back my mom used to work on Main-frames that ran COBOL on them and dumped out business data on paper at the end of the day. These reports had these printed bar charts.

I wrote a small ruby script to dump these charts on the console. The output looks like

D:\MyStuff\Code\Ruby>perf c:\logs\Recorder_20071118_144855.843.log
c:/logs/Recorder_20071118_144855.843.log ===============================>
  640 ********************************************************************************
    0 *
  109 *************
    0 *
   46 *****
    0 *

Serves the same purpose as their fancier counterpart but manages to look uber geeky.

Support for range in programming languages

The .NET platform and the languages on top of it have limited or no support for range of values. Data ranges are one of the most common data-types and somehow it's not there. Funnily most programmers do not even seem to miss it (unless of course if you have used Ruby).

How would you specify a valid range of age and validate user data against it? If you know the maximum and minimum values, at max you'd define a MaxAge and MinAge consts and strew the code with if(age < MinAge|| age >MaxAge). Or maybe you'll define a class to encapsulate this and add a IsValid method.

However, in Ruby, Range is a standard DataType like say string. To do the above processing you'd do

age = 1..120

print age.include?(50)
print age.include?(130)

 
print age === (50) # more easier way to do include? test using the === operator

So intuitively you create a range using start..stop.

Creating a range of data is also very simple. Say you want to generate the column numbers for an excel sheet, you'd do the following

column = 'A'..'ZZ'

column.to_a # creates an array of all the values

column.each {|v| puts "#{v}\n"}

Similarly ranges can be easily created for any class by implementing some special methods. On ruby the support of Range is in the compiler and makes the code very easy to develop and intuitive.

>>Cross posted here