# File lib/sass/script/tree/unary_operation.rb, line 60 def _perform(environment) operator = "unary_#{@operator}" value = @operand.perform(environment) value.send(operator) rescue NoMethodError => e raise e unless e.name.to_s == operator.to_s raise Sass::SyntaxError.new("Undefined unary operation: \"#{@operator} #{value}\".") end