Module: CssDryer::Processor

Included in:
CssDryer2::NcssHandler
Defined in:
lib/css_dryer_2/processor.rb

Defined Under Namespace

Classes: StateMachine, StyleHash

Constant Summary collapse

VERSION =
'0.4.0'

Instance Method Summary collapse

Instance Method Details

#nested_css_to_structure(css) ⇒ Object

:nodoc:


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# File 'lib/css_dryer_2/processor.rb', line 61

def nested_css_to_structure(css)  #:nodoc:
  # Implementation notes:
  # - the correct way to do this would be using a lexer and parser
  # - ironically there is a degree of repetition here
  document = []
  selectors = []
  media_block = false
  css.each do |line|
    depth = selectors.length
    case line.chomp!
    # Media block (multiline) opening - treat as plain text but start
    # watching for close of media block.
    # Assume media blocks are never themselves nested.
    # (This must precede the multiline selector condition.)
    when /^(\s*@media.*)[{]\s*$/
      media_block = true
      document << line if depth == 0
    # Media block inline
    # Assume media blocks are never themselves nested.
    when /^\s*@media.*[{].*[}]\s*$/
      document << line if depth == 0
    # Multiline selector opening
    when /^\s*([^{]*?)\s*[{]\s*$/
      hsh = StyleHash[ $1 => [] ]
      hsh.multiline = true
      if depth == 0
        document << hsh
      else
        prev_hsh = selectors.last
        prev_hsh.value << hsh
      end
      selectors << hsh
    # Neither opening nor closing - 'plain text'
    when /^[^{}]*$/
      if depth == 0
        document << line
      else
        hsh = selectors.last
        hsh.value << (depth == 1 ? line : line.strip)
      end
    # Multiline selector closing
    when /^([^{]*)[}]\s*$/
      if media_block
        media_block = false
        if depth == 0
          document << line
        else
          hsh = selectors.last
          hsh.value << line
        end
      else
        selectors.pop
      end
    # Inline selector
    when /^([^{]*?)\s*[{]([^}]*)[}]\s*$/
      key = (depth == 0 ? $1 : $1.strip)
      hsh = StyleHash[ key => [ $2 ] ]
      if depth == 0
        document << hsh
      else
        prev_hsh = selectors.last
        prev_hsh.value << hsh
      end
    end
  end
  document
end

#process(nested_css, indent = 2) ⇒ Object

Converts a stylesheet with nested styles into a flattened, normal CSS stylesheet. The original whitespace is preserved as much as possible.

For example, the following DRY stylesheet:

div {
  font-family: Verdana;
  #content {
    background-color: green;
    p { color: red; }
  }
}

is converted into this CSS:

div {
  font-family: Verdana;
}
div #content {
  background-color: green;
}
div #content p { color: red; }

Note, though, that @media blocks are preserved. For example:

@media screen, projection {
  div {font-size:100%;}
}

is left unchanged.

Styles may be nested to an arbitrary level.


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# File 'lib/css_dryer_2/processor.rb', line 55

def process(nested_css, indent = 2)  #:doc:
  # 'Normalise' comma separated selectors
  nested_css = factor_out_comma_separated_selectors(nested_css, indent)
  structure_to_css(nested_css_to_structure(nested_css), indent)
end

#structure_to_css(structure, indent = 2) ⇒ Object

:nodoc:


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# File 'lib/css_dryer_2/processor.rb', line 129

def structure_to_css(structure, indent = 2)  #:nodoc:
  # Implementation note: the recursion and the formatting
  # ironically both feel repetitive; DRY them.
  indentation = ' ' * indent
  css = ''
  structure.each do |elem|
    # Top-level hash
    if elem.kind_of? StyleHash
      set_asides = []
      key = elem.key
      if elem.has_non_style_hash_children
        css << "#{key} {"
        css << (elem.multiline ? "\n" : '')
      end
      elem.value.each do |v|
        # Nested hash, depth = 1
        if v.kind_of? StyleHash
          # Set aside
          set_asides << set_aside(combo_key(key, v.key), v.value, v.multiline)
        else
          unless v.blank?
            css << (elem.multiline ? "#{v}" : v)
            css << (elem.multiline ? "\n" : '')
          end
        end
      end
      css << "}\n" if elem.has_non_style_hash_children
      # Now write out the styles that were nested in the above hash
      set_asides.flatten.each { |hsh|
        next unless hsh.has_non_style_hash_children
        css << "#{hsh.key} {"
        css << (hsh.multiline ? "\n" : '')
        hsh.value.each { |item|
          unless item.blank?
            css << (hsh.multiline ? "#{indentation}#{item}" : item)
            css << (hsh.multiline ? "\n" : '')
          end
        }
        css << "}\n"
      }
      set_asides.clear
    else
      css << "#{elem}\n"
    end
  end
  css
end