From: Robert Klemme <shortcutter@...>
Date: 2007-05-06T22:35:04+09:00
Subject: Re: fixnum, range and array into one single loop?

On 06.05.2007 15:20, anansi wrote:
> Hi,
> I'm struggeling with writing a little script. It has a loop just e.g. 
> like this:
> 
> for x in 1..10 do
> begin
>  puts "#{x}"
> end
> 
> The userinput is the loop count (so above the userinput would have been 
> 1..10): but now this userinput can be a fixnum like 12 or 36 or it can 
> be a range like 1..10 or 24..84 or an array like [23,41,35,63] and for 
> every 3 different input kinds the loop shall do the same.
> 
> Like in this example:
> 
> If userinput is just fixnum 11 it just prints 11 on the screen, is it a 
> range from 1..10 all numbers from 1..10 shall be printed and for an 
> array all single numbers stored in the array...you know what I mean. The 
> actual routine doesn't print anything it's just about I have to process 
> numbers which can the user give in, in three different ways and I was 
> wondering if it is possible to build this into one single loop and not 
> three different ones?

How about

def my_loop(x,&b)
   case x
     when /\A\d+\z/
       x.to_i.times(&b)
     when /\A(\d+)\.\.(\d+)\z/
       ($1.to_i .. $2.to_i).each(&b)
     when /\A\[\s*\d+\s*(?:,\s*\d+\s*)*\]\z/
       eval(x).each(&b)
     else
       raise ArgumentError, "Don't know what to do with: #{x}"
   end
end

 >> my_loop("5") {|x| p x}
0
1
2
3
4
=> 5
 >> my_loop("1..5") {|x| p x}
1
2
3
4
5
=> 1..5
 >> my_loop("[5,3,2]") {|x| p x}
5
3
2
=> [5, 3, 2]
 >> my_loop("1,2") {|x| p x}
ArgumentError: Don't know what to do with: 1,2
         from (irb):10:in `my_loop'
         from (irb):16
         from :0
 >>

Kind regards

	robert