From: hemant <gethemant@...>
Date: 2006-11-08T17:19:24+09:00
Subject: Re: understanding send

On 11/8/06, gaurav bagga <gaurav.v.bagga@gmail.com> wrote:

The problem is hidden in following lines. There is no problem with
doing send on methods.


> class MyNewClass
>   attr_accessor :name,:place,:age
> end
> a=[]
> 1.upto(3) do
>   val=MyNewClass.new
>   val.instance_variables.each do |met|
>    val.send(met.delete("@")+"=",gets.chomp!)
>   end
>  a<<val
> end

You are trying to define some attributes, through attr_accessor. Now,
what attr_accessor does? It sets couple of instance methods
automatically on your class. So...if you do:
val.instance_variables.each do|x|
p x
end

You will get an empty list. Why? Because your instance variables are
not there yet. What probably you want to do is..get instance_methods
and set your instance_variables there. Until you set them
up..."val.instance_variables" will contain a empty list. and hence all
the subsequent lines will fail.


> a.each do |val|
>  val.instance_variables.each do |met|
>   p val.send(met.delete("@"))
>  end
> end
> a.each do |val|
>  MyNewClass.instance_methods(false).select{
>    |v| v =~ /[=$]/
>  }.each do |met|
>   val.send(met,gets.chomp!)
>  end
> end
>
> a.each do |val|
>  MyNewClass.instance_methods(false).select{
>    |v| v =~ /[a-z]$/
>  }.each do |met|
>    p val.send(met)
>  end
> end
>
>
> hi all,
>  can any one tell me whats wrong with this code its not working for
>  val.send(met.delete("@")+"=",gets.chomp!)
>
> if instead of  val.send(met.delete("@")+"=",gets.chomp!) i give
> val.name=gets.chomp!..... it works
>
> regards
> gaurav v bagga
>
>



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