Is this a kind of design patterns?

ruby-talk
21

Robert Klemme wrote:

Since we're in Color anyway, you can simplify the definition that by

I like that.

And I love the collective refactoring that goes on in this list!

···

--
-- Jim Weirich

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

22

I have a bunch of template documents which I need to manipulate in very simple ways. I'd like to be able to insert Ruby variables into the template. Here is a very short example:

file fruit_template.txt: This is a fruit: #{fruit}.

fruit = "apple"
f = IO.read("fruit_template.txt")

Then somehow I'd like to end up with this string:
"This is a fruit: apple."

The easy answer to your question is to use eval():

>> fruit = "apple"
=> "apple"
>> f = 'This is a fruit: #{fruit}.'
=> "This is a fruit: \#{fruit}."
>> eval %Q{"#{f}"}
=> "This is a fruit: apple."

The right answer is to use a template library, like the standard ERB:

>> f = "This is a fruit: <%= fruit %>."
=> "This is a fruit: <%= fruit %>."
>> require "erb"
=> true
>> ERB.new(f).result(binding)
=> "This is a fruit: apple."

Hope that helps.

James Edward Gray II

···

On Mar 23, 2006, at 3:31 PM, Stephen Bannasch wrote:

23

I got great improvements to make color usage enterprise ready...

Here comes my first class color object using state-of-the-art
design patterns for better scalability and performance

I was designed using the rational design process + UML

class ColorRegistry
private

  def self.mix(*colors)
    r,g,b=[0,0,0]
    while color = colors.shift
      r += color[0]
      g += color[1]
      b += color[2]
    end
    [r,g,b]
  end

  RED = [255,0,0]
  GREEN = [0,0b11111111,0]
  BLUE = [0,0,0xff]
  WHITE = mix(RED, GREEN, BLUE)
  YELLOW = mix(RED, GREEN)
  # more to come

public
  def self.get_binding
    binding
  end

end

class ColorEvaluator
  def self.get(name)
    eval(name.upcase, ColorRegistry.get_binding)
  end
end

puts ColorEvaluator.get("yellow")
puts ColorEvaluator.get("red")
puts ColorEvaluator.get("white")

···

--- Ursprüngliche Nachricht ---
Von: Jim Weirich <jim@weirichhouse.org>
An: ruby-talk@ruby-lang.org (ruby-talk ML)
Betreff: Re: Is this a kind of design patterns?
Datum: Fri, 24 Mar 2006 01:13:52 +0900

Robert Klemme wrote:
> Since we're in Color anyway, you can simplify the definition that by

I like that.

And I love the collective refactoring that goes on in this list!

--
-- Jim Weirich

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