select_tag_helper.rb

# -*- coding: utf-8 -*-

module SelectTagHelper


  ##
  ## Generate <select> tag. Both <option> and <opttags> are supported.
  ##
  ## ex.
  ##    <% values = {'H'=>'Haruhi', 'M'=>'Mikuru', 'Y'=>'Yuki'} %>
  ##    <%= select_tag('yome', 'H', 'class="yome"') do |t|
  ##          t.option(nil, 'Please select')
  ##          values.each {|k,v| t.option(k, v) }
  ##        end %>
  ##
  ##    #=> <select name="yome" class="yome">
  ##    #   <option value="">Please select</option>
  ##    #   <option value="H" selected="selected">Haruhi</option>
  ##    #   <option value="M">Mikuru</option>
  ##    #   <option value="Y">Yuki</option>
  ##    #   </select>
  ##
  ## ex.
  ##    <% girls = {'H'=>'Haruhi', 'M'=>'Mikuru', 'Y'=>'Yuki'} %>
  ##    <% boys  = {'I'=>'Itsuki', 'K'=>'Kyon'} %>
  ##    <%= select_tag('yome', 'H', :class=>"yome") do |t|
  ##          t.option(nil, 'Please select')
  ##          t.optgroup('Girls') do girls.each {|k, v| t.option(k, v) } end
  ##          t.optgroup('Boys')  do boys.each  {|k, v| t.option(k, v) } end
  ##        end %>
  ##
  ##    #=> <select name="yome" class="yome">
  ##    #   <option value="">Please select</option>
  ##    #   <optgroup label="Girls">
  ##    #   <option value="H" selected="selected">Haruhi</option>
  ##    #   <option value="M">Mikuru</option>
  ##    #   <option value="Y">Yuki</option>
  ##    #   </optgroup>
  ##    #   <optgroup label="Boys">
  ##    #   <option value="I">Itsuki</option>
  ##    #   <option value="K">Kyon</option>
  ##    #   </optgroup>
  ##    #   </select>
  ##
  def select_tag(name, value, attrs=nil, &block)
    return SelectTag.new.build(name, value, attrs, &block)
  end


  ##
  ## Generate <select multiple="multiple"> tag.
  ##
  ## 'values' arguments can be an Array, Hash, or scalar value.
  ##
  def multiple_select_tag(name, values, attrs=nil, &block)
    return MultipleSelectTag.new.build(name, values, attrs, &block)
  end


  ##
  ## Helper class for select_tag() method
  ##
  class SelectTag   # :nodoc:

    def build(name, value=nil, attrs=nil)
      @value = value
      @tag = "<select name=\"#{name}\"#{tag_attr_str(attrs)}>\n"
      yield self
      @tag << "</select>"
      @tag
    end

    def option(val, label=nil, attrs=nil)
      label = val if label.nil?
      s1 = selected?(val) ? ' selected="selected"' : nil
      s2 = tag_attr_str(attrs)
      @tag << "<option value=\"#{val}\"#{s1}#{s2}>#{label}</option>\n"
    end

    def optgroup(label, attrs=nil)
      @tag << "<optgroup label=\"#{label}\">\n"
      yield self
      @tag << "</optgroup>\n"
    end

    private

    def tag_attr_str(html)
      case html
      when nil    ;  nil
      when String ;  " #{html}"
      when Hash   ;  html.collect {|k, v| " #{k}=\"#{v}\"" }.join
      else        ;  raise ArgumentError.new("#{html.inspect}: String or Hash expected")
      end
    end

    def selected?(val)
      @value == val && ! val.nil?
    end

  end


  ##
  ## Helper class for multiple_select_tag() method
  ##
  class MultipleSelectTag < SelectTag    # :nodoc:

    def build(name, values=nil, attrs=nil, &block)
      set_values(values)
      @tag = "<select name=\"#{name}\" multiple=\"multiple\"#{tag_attr_str(attrs)}>\n"
      yield self
      @tag << "</select>"
      @tag
    end

    private

    def set_values(values)
      case values
      when nil        ;  @values = {}
      when Hash       ;  @values = values
      when Enumerable ;  @values = {}
                         values.each {|x| @values[x] = true }
      else            ;  @values = {values => true}
      end
    end

    def selected?(val)
      @values.include?(val)
    end

  end


end


if __FILE__ == $0

  ARGV.concat(%w[-f nested -c])   # or %w[-D -f nested]

  require 'rubygems'
  require 'spec'

  ## describe のかわりに specs_of を、また it のかわりに spec を使う
  Spec::DSL::Main.module_eval { alias specs_of describe }
  Spec::Example::ExampleGroupMethods.module_eval { alias spec it }

  Object.class_eval { include SelectTagHelper }

  specs_of SelectTagHelper, "#select_tag()" do
    girls = {'H'=>'Haruhi', 'M'=>'Mikuru', 'Y'=>'Yuki'}
    boys  = {'I'=>'Itsuki', 'K'=>'Kyon'}
    expected1 = <<'END'
<select name="yome" class="yome">
<option value="">Please select</option>
<option value="H" selected="selected">Haruhi</option>
<option value="M">Mikuru</option>
<option value="Y">Yuki</option>
</select>
END
    expected1.chomp!
    expected2 = <<'END'
<select name="yome" class="yome">
<option value="">Please select</option>
<optgroup label="Girls">
<option value="H" selected="selected">Haruhi</option>
<option value="M">Mikuru</option>
<option value="Y">Yuki</option>
</optgroup>
<optgroup label="Boys">
<option value="I">Itsuki</option>
<option value="K">Kyon</option>
</optgroup>
</select>
END
    expected2.chomp!

    spec "<select> タグを生成する" do
      html = select_tag('yome', nil, 'class="yome"') do |t|
        t.option(nil, 'Please select')
        girls.each {|k,v| t.option(k, v) }
      end
      html.should == expected1.sub(/ selected="selected"/, '')
    end

    spec "現在値が指定されたら <option> タグに 'selected' 属性を追加する" do
      html = select_tag('yome', 'H', 'class="yome"') do |t|
        t.option(nil, 'Please select')
        girls.each {|k,v| t.option(k, v) }
      end
      html.should == expected1
    end

    spec "<option> タグと同様に <optgroup> タグもサポートする" do
      html = select_tag('yome', nil, 'class="yome"') do |t|
        t.option(nil, 'Please select')
        t.optgroup('Girls') do
          girls.each {|k, v| t.option(k, v) }
        end
        t.optgroup('Boys') do
          boys.each {|k, v| t.option(k, v) }
        end
      end
      html.should == expected2.sub(/ selected="selected"/, '')
    end

  end

  specs_of SelectTagHelper, "#multiple_selected()" do
    girls = {'H'=>'Haruhi', 'M'=>'Mikuru', 'Y'=>'Yuki'}
    boys  = {'I'=>'Itsuki', 'K'=>'Kyon'}
    expected1 = <<'END'
<select name="yome" multiple="multiple" class="yome">
<option value="">Please select</option>
<option value="H" selected="selected">Haruhi</option>
<option value="M">Mikuru</option>
<option value="Y" selected="selected">Yuki</option>
</select>
END
    expected1.chomp!
    expected2 = <<'END'
<select name="yome" multiple="multiple" class="yome">
<option value="">Please select</option>
<optgroup label="Girls">
<option value="H" selected="selected">Haruhi</option>
<option value="M">Mikuru</option>
<option value="Y">Yuki</option>
</optgroup>
<optgroup label="Boys">
<option value="I">Itsuki</option>
<option value="K" selected="selected">Kyon</option>
</optgroup>
</select>
END
    expected2.chomp!

    spec "'multiple' 属性つきの <select> タグを生成する" do
      html = multiple_select_tag('yome', nil, 'class="yome"') do |t|
        t.option(nil, 'Please select')
        girls.each {|k, v| t.option(k, v) }
      end
      html.should == expected1.gsub(/ selected="selected"/, '')
    end

    spec "現在値が配列で指定されたら <option> タグに 'selected' 属性を追加する" do
      html = multiple_select_tag('yome', ['H', 'Y'], 'class="yome"') do |t|
        t.option(nil, 'Please select')
        girls.each {|k, v| t.option(k, v) }
      end
      html.should == expected1
    end

    spec "現在値がHashで指定されたら <option> タグに 'selected' 属性を追加する" do
      html = multiple_select_tag('yome', {'H'=>true, 'Y'=>true}, 'class="yome"') do |t|
        t.option(nil, 'Please select')
        girls.each {|k, v| t.option(k, v) }
      end
      html.should == expected1
    end

    spec "現在値が文字列や数値で指定されたら <option> タグに 'selected' 属性を追加する" do
      html = multiple_select_tag('yome', 'Y', 'class="yome"') do |t|
        t.option(nil, 'Please select')
        girls.each {|k, v| t.option(k, v) }
      end
      html.should == expected1.sub(/ selected="selected"/, '')   # remove the first one
    end

    spec "<option> タグだけでなく <optgroups> タグもサポートする" do
      html = multiple_select_tag('yome', ['H', 'K'], 'class="yome"') do |t|
        t.option(nil, 'Please select')
        t.optgroup('Girls') do
          girls.each {|k, v| t.option(k, v) }
        end
        t.optgroup('Boys') do
          boys.each {|k, v| t.option(k, v) }
        end
      end
      html.should == expected2
    end

  end

  require 'spec/autorun'
  exit Spec::Runner::CommandLine.run

end