// character to ASCII value: use ?

?a     # => 97
?\n    # => 10

// string to integer: use []

'a'[0]        # => 97
'hallo'[1]    # => 97

// integer / number to character: use .chr

97.chr     # => "a"
10.chr     # => "\n"

//more info: "Ruby Cookbook", O'Reilly

// radio buttons generated with form helper
// selection by boolean
// attention interger numbers (0, 1) don't work

    <div class="row">
      <dl>
        <dt>Owner over 18?</dt>
        <dd>
        <%= radio_button( :guarantor, :over_eighteen.to_s, true )%> Yes &nbsp;&nbsp;
        <%= radio_button( :guarantor, :over_eighteen, false )%> No
        </dd>
      </dl>
    </div>

// camelize - from underscore_syntax to Uppercas/ClassSyntax
// constantize - create instance
// (params[:property]) -- read data from web-form

    @property = property_type.camelize.constantize.new(params[:property])

// in radrails when you import a project from subversion
// it is a normal project

// in the menu I found no way to transform it
// but so it worked for me:

// 1. edit the .project file and copy the natueres block

	<natures>
		<nature>org.radrails.rails.ui.railsnature</nature>
		<nature>org.rubypeople.rdt.core.rubynature</nature>
	</natures>

// 2. copy the buildSpec block too
// (I'm not sure if this is necessary, I did both and it worked)

	<buildSpec>
		<buildCommand>
			<name>org.rubypeople.rdt.core.rubybuilder</name>
			<arguments>
			</arguments>
		</buildCommand>
	</buildSpec>

// 3. restart radrails and
// 4. add a webrick-server to the project
// and you are done

// find out the current url / uri in *.rhtml file
// is quite simple with the request object

<% page = request.request_uri %>
page: <%= page %>

// but then different urls mean the same page
// (../admin = ../admin/ = ../admin/index = ..admin/index/)
// and maybe the id is unwanted too (../admin/show/8)
// so below is an alternative with control on which parameter is used

<% page = "/" + request.path_parameters['controller'] + "/" + request.path_parameters['action'] %>
page: <%= page %>

// generate application

rails projectname

// generate migration.

ruby script/generate migration migration_name
ruby script/generate migration add_price

// generate model
// we can give a list of columns and types
// :string, :text, :integer, :decimal, :float, :date, ...

ruby script/generate model model_name
ruby script/generate model user name:string hashed_password:string salt:string

// generate controller

ruby script/generate controller controller_name method_name(s)
ruby script/generate controller store index

// generate scaffold

ruby script/generate scaffold model_name controller_name
ruby script/generate scaffold product admin

// the parameter is written behind the operator in parantheses
// the parameter must be an integer/fixnum
//
// i.e.
// def [](chunk)
// @internal_id_hash[chunk.chunk_id]
// end
// is not possible

class ChunkList
  ..

  def [](chunk_id)
    @internal_id_hash[chunk_id]
  end
end

// simple singleton

class Singleton 
  private_class_method :new
  @@singleton = nil
  
  def Singleton.create
    @@singleton = new unless @@singleton
    @@singleton
  end
end

// Sample Output, "character (byte) occurs n times", 32 = space
// s (115) occurs 3 times
// n (110) occurs 1 times
// ..
// (32) occurs 3 times

class Counter
  
def initialize()
  @characters = Hash.new(0)
end

def read()
  @text = IO.read("text.txt")
end

def count_chars
  @text.each_byte do |ch|
  @characters[ch] +=1
  end
end

def report  
  @characters.each do |key, value|
    puts "#{key.chr} (#{key}) occurs #{value} times"
  end  
end

end

// usage

count = Counter.new()
count.read
count.count_chars
count.report

// works only in mozilla

<style type="text/css">
<!--

    option[value=ohcon]:before { content:url("ohc.gif"); }
    option[value=baerlin]:before { content:url("baer.gif"); }
    option[value=zendo]:before { content:url("zendo.gif"); }

-->
</style>

..

Select Company
<select>
  <option value="ohcon">Oliver Haag IT consulting</option>
  <option value="baerlin">Bärlin Partners</option>
  <option value="zendo">Zendo-Marketing</option>  
</select>