class Temple::ERB::Trimming

def code?(exp)
  exp[0] == :dynamic || exp[0] == :block
end

def on_multi(*exps)
  case options[:trim_mode]
  when '>'
    exps.each_cons(2) do |a, b|
      if code?(a) && static?(b)
        b[1].gsub!(/^\n/, '')
      end
    end
  when '<>'
    exps.each_with_index do |exp, i|
      if code?(exp) &&
          (!exps[i-1] || static?(exps[i-1]) && exps[i-1][1] =~ /\n$/) &&
          (exps[i+1] && static?(exps[i+1]) && exps[i+1][1] =~ /^\n/)
        exps[i+1][1].gsub!(/^\n/, '') if exps[i+1]
      end
    end
  end
  [:multi, *exps]
end

def static?(exp)
  exp[0] == :static
end