Intra-module method calls

ruby-talk
1

I have a module named X

module X

end

I would like to call one method from another in my module.

If I do

public
def method1
...
method2
end

private
def method2
...
end

why doesn't this work? Is it because this isn't a class and the
"private" keyword isn't meaningful?

Thanks,
Wes

···

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2

Sorry, I wasn't clear enough - my question is why does the call to
method2 from method1 fail with a

undefined method `method2' for X:Module

error?

Thanks,
WG

Wes Gamble wrote:

···

I have a module named X

module X

end

I would like to call one method from another in my module.

If I do

public
def method1
...
method2
end

private
def method2
...
end

why doesn't this work? Is it because this isn't a class and the
"private" keyword isn't meaningful?

Thanks,
Wes

--
Posted via http://www.ruby-forum.com/\.

3

Wes Gamble wrote:

Sorry, I wasn't clear enough - my question is why does the call to
method2 from method1 fail with a

undefined method `method2' for X:Module

Is the following what you are doing ?

   irb(main):007:0> module X
   irb(main):008:1> public
   irb(main):009:1> def method1
   irb(main):010:2> "method1" + method2
   irb(main):011:2> end
   irb(main):012:1> private
   irb(main):013:1> def method2
   irb(main):014:2> "method2"
   irb(main):015:2> end
   irb(main):016:1> end
   => nil
   irb(main):017:0> class A
   irb(main):018:1> include X
   irb(main):019:1> end
   => A
   irb(main):020:0> A.new.method1
   ---------------------^^^^^^^^^^---------------
   irb(main):021:0> A.new.method1
   => "method1method2"

Because the above should work just fine. If the above is not what you
are seeing, please post the code so we can better help.

Zach

4

I just want to have some utility methods for use by my app.
The code below works.
Notice the calls to add_default_path in the other two methods.

My question is: why do I have to qualify the name of add_default_path
with ESimplyUtil since no external code is calling that method? Why
can't I just have

def add_default_path
end

?

Thanks,
WG

···

===================

Here's my module:

module ESimplyUtil
  public
  def ESimplyUtil.validate_and_format_url(in_url)
    begin
      url = URI.parse(in_url)
    rescue
      raise("This is not a valid URL")
    end

    #If the URL is valid HTTP URL, default the path if necessary
    #If the URL is generic make it into an HTTP URL
    # Get the host - match the first set of non-/ characters
    # Get the path - match all of the characters including the first
slash
    #If the URL is a valid non-HTTP URL, then it's an error.
    if (url.instance_of?(URI::HTTP))
      url = add_default_path(url)
    elsif (url.instance_of?(URI::Generic))
      if (((url.scheme != nil) && (url.scheme != "http")) ||
          (url.path.nil?) || (url.path == ''))
        raise("This is not a valid URL")
      else
        port = 80
        host = url.path.match(/[^\/]+/)[0]
        path_match = url.path.match(/\/(.*)/)
        if (path_match.nil?)
          path = '/'
        else
          path = path_match[0]
        end

        url = URI::HTTP.new('http', nil, host, 80, nil, path, nil, nil,
nil)
      end
    elsif (! url.instance_of?(URI::HTTP))
      raise("This is not a valid URL")
    end

    url
  end

  public
  def ESimplyUtil.get_URL(myURL)
    url = URI.parse(myURL)
    url = add_default_path(url)
    req = Net::HTTP::Get.new(url.path)
    res = Net::HTTP.start(url.host, url.port) {|http|
      http.request(req)
    }

    res
  end

  private
  def ESimplyUtil.add_default_path(url)
    if ((url.path == '') || (url.path.nil?))
      url.path = '/'
    end

    url
  end
end

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5

module ESimplyUtil

[...]

  private
  def ESimplyUtil.add_default_path(url)

Be carefull, ruby will not do what you think

moulon% cat b.rb
#!/usr/bin/ruby
module A
   private
   def self.a
   end

   class << self
      private
      def b
      end
   end
end

["a", "b"].each do |m|
   puts "#{m}() private ? #{A.private_methods.include?(m)}"
   puts "#{m}() public ? #{A.public_methods.include?(m)}"
end

moulon%

moulon% ./b.rb
a() private ? false
a() public ? true
b() private ? true
b() public ? false
moulon%

Guy Decoux

6

So, in normal language, does that mean that "private" is not meaningful
within the context of a module?

Thanks,
Wes

ts wrote:

···

> module ESimplyUtil

[...]

> private
> def ESimplyUtil.add_default_path(url)

Be carefull, ruby will not do what you think

moulon% cat b.rb
#!/usr/bin/ruby
module A
   private
   def self.a
   end

   class << self
      private
      def b
      end
   end
end

["a", "b"].each do |m|
   puts "#{m}() private ? #{A.private_methods.include?(m)}"
   puts "#{m}() public ? #{A.public_methods.include?(m)}"
end

moulon%

moulon% ./b.rb
a() private ? false
a() public ? true
b() private ? true
b() public ? false
moulon%

Guy Decoux

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