class Sass::Script::Tree::Interpolation

def _perform(environment)
  res = ""
  res << @before.perform(environment).to_s if @before
  res << " " if @before && @whitespace_before
  val = @mid.perform(environment)
  if @warn_for_color && val.is_a?(Sass::Script::Value::Color) && val.name
    alternative = Operation.new(Sass::Script::Value::String.new("", :string), @mid, :plus)
    Sass::Util.sass_warn <<MESSAGE
ING on line #{line}, column #{source_range.start_pos.offset}#{" of #{filename}" if filename}:
probably don't mean to use the color value `#{val}' in interpolation here.
ay end up represented as #{val.inspect}, which will likely produce invalid CSS.
ys quote color names when using them as strings (for example, "#{val}").
ou really want to use the color value here, use `#{alternative.to_sass}'.
AGE
  end
  res << val.to_s(:quote => :none)
  res << " " if @after && @whitespace_after
  res << @after.perform(environment).to_s if @after
  str = Sass::Script::Value::String.new(
    res, :identifier,
    (to_quoted_equivalent.to_sass if deprecation == :potential))
  str.source_range = source_range
  opts(str)
end

def children
  [@before, @mid, @after].compact
end

def concat(string_or_interp1, string_or_interp2)
  if string_or_interp1.is_a?(Literal) && string_or_interp2.is_a?(Literal)
    return string_literal(string_or_interp1.value.value + string_or_interp2.value.value)
  end
  if string_or_interp1.is_a?(Literal)
    string = string_or_interp1
    interp = string_or_interp2
    before = string_literal(string.value.value + interp.before.value.value)
    return StringInterpolation.new(before, interp.mid, interp.after)
  end
  StringInterpolation.new(
    string_or_interp1.before,
    string_or_interp1.mid,
    concat(string_or_interp1.after, string_or_interp2))
end

def deep_copy
  node = dup
  node.instance_variable_set('@before', @before.deep_copy) if @before
  node.instance_variable_set('@mid', @mid.deep_copy)
  node.instance_variable_set('@after', @after.deep_copy) if @after
  node
end

def initialize(before, mid, after, wb, wa, opts = {})
  @before = before
  @mid = mid
  @after = after
  @whitespace_before = wb
  @whitespace_after = wa
  @originally_text = opts[:originally_text] || false
  @warn_for_color = opts[:warn_for_color] || false
  @deprecation = opts[:deprecation] || :none
end

def inspect
  "(interpolation #{@before.inspect} #{@mid.inspect} #{@after.inspect})"
end

def string_literal(string)
  Literal.new(Sass::Script::Value::String.new(string, :string))
end

def to_quoted_equivalent
  Funcall.new(
    "unquote",
    [to_string_interpolation(self)],
    Sass::Util::NormalizedMap.new,
    nil,
    nil)
end

def to_sass(opts = {})
  return to_quoted_equivalent.to_sass if deprecation == :immediate
  res = ""
  res << @before.to_sass(opts) if @before
  res << ' ' if @before && @whitespace_before
  res << '#{' unless @originally_text
  res << @mid.to_sass(opts)
  res << '}' unless @originally_text
  res << ' ' if @after && @whitespace_after
  res << @after.to_sass(opts) if @after
  res
end

def to_string_interpolation(node_or_interp)
  unless node_or_interp.is_a?(Interpolation)
    node = node_or_interp
    return string_literal(node.value.to_s) if node.is_a?(Literal)
    if node.is_a?(StringInterpolation)
      return concat(string_literal(node.quote), concat(node, string_literal(node.quote)))
    end
    return StringInterpolation.new(string_literal(""), node, string_literal(""))
  end
  interp = node_or_interp
  after_string_or_interp =
    if interp.after
      to_string_interpolation(interp.after)
    else
      string_literal("")
    end
  if interp.after && interp.whitespace_after
    after_string_or_interp = concat(string_literal(' '), after_string_or_interp)
  end
  mid_string_or_interp = to_string_interpolation(interp.mid)
  before_string_or_interp =
    if interp.before
      to_string_interpolation(interp.before)
    else
      string_literal("")
    end
  if interp.before && interp.whitespace_before
    before_string_or_interp = concat(before_string_or_interp, string_literal(' '))
  end
  concat(before_string_or_interp, concat(mid_string_or_interp, after_string_or_interp))
end