From: Pierre Lecocq <pierre.lecocq@...>
Date: 2010-04-27T22:38:13+09:00
Subject: Variable number of arguments for methods called with "send"

Hi there,


I have a (soooo) dummy class :


# --

class Main < XXXXX

  def time
    'Il est ' + Time.now.to_s
  end

  def salut
    ['salut', 'les', 'muscl辿s']
  end

  def test_with_args(arg1, arg2)
    [arg1, arg2]
  end

  def test_with_multiple_args(*args)
    args
  end

end

# /--




In a configuration file, I have the name of the methods and their
arguments if they need some:



# --

config:
  aff_bonjour: __SALUT
  aff_temps: __TIME
  tab_toto: __TEST_WITH_ARGS 'toto', 53

# /--




In another script, I get back the config file and try to call the
lethods in order to stack their results.
In order to do that, I wrote something like:


# --

vars = {}
config = YAML::load('config.yml') # the config file described previously
@name = 'Main'   # got from config file
obj = Object.const_get(@name).new  # Create the object
config.each do |key, value|
  if value =~ /^__(.+)/ and !obj.nil?
    tmp = value.gsub(/^__/, '').downcase.split(' ')
    method = tmp[0]  # get the method name
    tmp.delete_at 0  # delete method name from the array
    tmp.map do |e|
      e.gsub!(/,/, '')  # clean up remaining args
      e.strip!
    end
    vars[key.to_s] = obj.send(method.to_sym) if obj.respond_to? method
  else
    vars[key.to_s] = value
  end
end

# /--



Here is the small description

 1. After preparing the object, I check every line of my config
 2. if it is a method (begins by '__'), I get the optional args

    e.g:   "tab_toto: __TEST_WITH_ARGS 'toto', 53"
             "test_with_args" is the method
             'toto' and 53 are the args

 3. I call the method by invoking "obj.send(method.to_sym)"
 4 (back to 2) and if it is not a method, I just copy the static value
to my "vars" hash




And here is my problem :

for a method that does not take any argument (like "time" or "salut"),
there is no problem, it works like a charm.

But if I want to call a method with arguments, I am stuck because I do
not know how many arguments it needs and what is the "kind" of arguments
(can be "static arguments" - arg1, arg2 - or VARGS - *args - )

How can I call a method with a dynamic array (even empty) to cover all
the different kind of methods of my "Main" class ?

Or is there any other solution for that ?




I do not know if those explanations are clear enough, tell me if not.

Thank you for your potential help,
Regards,

Pierre
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