class Object # Invokes the public method identified by the symbol +method+, passing it any arguments # and/or the block specified, just like the regular Ruby Object#public_send does. # # *Unlike* that method however, a +NoMethodError+ exception will *not* be raised # and +nil+ will be returned instead, if the receiving object is a +nil+ object or NilClass. # # This is also true if the receiving object does not implemented the tried method. It will # return +nil+ in that case as well. # # If try is called without a method to call, it will yield any given block with the object. # # Please also note that +try+ is defined on +Object+, therefore it won't work with # subclasses of +BasicObject+. For example, using try with +SimpleDelegator+ will # delegate +try+ to target instead of calling it on delegator itself. # # Without +try+ # @person && @person.name # or # @person ? @person.name : nil # # With +try+ # @person.try(:name) # # +try+ also accepts arguments and/or a block, for the method it is trying # Person.try(:find, 1) # @people.try(:collect) {|p| p.name} # # Without a method argument try will yield to the block unless the receiver is nil. # @person.try { |p| "#{p.first_name} #{p.last_name}" } # # +try+ behaves like +Object#public_send+, unless called on +NilClass+. def try(*a, &b) if a.empty? && block_given? yield self else public_send(*a, &b) if respond_to?(a.first) end end end class NilClass # Calling +try+ on +nil+ always returns +nil+. # It becomes specially helpful when navigating through associations that may return +nil+. # # nil.try(:name) # => nil # # Without +try+ # @person && !@person.children.blank? && @person.children.first.name # # With +try+ # @person.try(:children).try(:first).try(:name) def try(*args) nil end end