Combine @item.foo.nil? || @item.foo.empty??

Ruby
1

I have code like this in my (Markaby) templates:

tr do
td @item.foo
end unless (@item.foo.nil? || @item.foo.empty?)

Is there a way to combine these two OR clauses into one?

tr do
td @item.foo
end unless @item.foo.nil_or_empty?

Thanks,
Joe

2

tr do
td @item.foo
end unless (@item.foo.nil? || @item.foo.empty?)

Is there a way to combine these two OR clauses into one?

Define a method on the class of foo?

class Foo
def nil_or_empty?
return nil? || empty?
end
end

3

Matthew M. wrote:

tr do
td @item.foo
end unless (@item.foo.nil? || @item.foo.empty?)

Is there a way to combine these two OR clauses into one?

Define a method on the class of foo?

class Foo
^^^
Object
def nil_or_empty?
return nil? || empty?
end
end

Otherwise it won’t be defined when foo==nil.

4

[email protected] writes:

tr{ tr @item.foo } unless @item.foo.to_s.empty?

It makes sense to me that

object.to_s.empty? # => true

should imply

object.empty? # => true

So why not just do

class NilClass
  def empty?; true; end
end

?

-Marshall

5

On Sat, 9 Sep 2006, Marshall T. Vandegrift wrote:

object.empty? # => true

So why not just do

class NilClass
def empty?; true; end
end

?

-Marshall

def deep_in_some_other_unrelated_code
begin
should_always_be_empty = buggy_method

   abort unless should_always_be_empty.empty?  # OOPS!

   transfer_four_million_euros_to_swiss_account
 rescue
   hours_of_debugging?
 ensure
   modify_builtins_with_care!
 end

end

-a

6

On Sat, 9 Sep 2006, Joe R. wrote:

end unless @item.foo.nil_or_empty?

Thanks,
Joe

tr{ tr @item.foo } unless @item.foo.to_s.empty?

-a

7

On Sep 9, 2006, at 10:37 AM, Marshall T. Vandegrift wrote:

object.empty? # => true

Doesn’t to me. nil is not a container, and it should not be treated
as one. A string is a container (contains a sequence of characters)
and can therefore be empty. The fact that one, arbitrary string
representation of nil happens to be the empty string doesn’t mean
that nil is empty. (This is also why I disklike rails’s #blank?, but
at least it’s named something different.)

8

On Sat, 09 Sep 2006 06:53:59 +0900, Joel VanderWerf wrote:

class Foo
^^^
Object
def nil_or_empty?
return nil? || empty?
end
end

Otherwise it won’t be defined when foo==nil.

So define as follows:

class NilClass
def nil_or_empty?
true
end
end

9

On 08/09/06, Joe R. [email protected] wrote:

end unless @item.foo.nil_or_empty?

Thanks,
Joe

–
Posted via http://www.ruby-forum.com/.

tr do
td @item.foo
end unless Array(@item).empty?

10

On 9/8/06, Joe R. [email protected] wrote:

td @item.foo
end unless @item.foo.nil_or_empty?

Thanks,
Joe

Perhaps #blank? from activesupport [1] could do what you want?

-Scott

[1]
http://dev.rubyonrails.org/browser/tags/rel_1-1-6/activesupport/lib/active_support/core_ext/blank.rb

11

On 9/9/06, Marshall T. Vandegrift [email protected] wrote:

class NilClass
  def empty?; true; end
end

Because nil isn’t empty.

It isn’t a container. It’s not an array, hash, or string.

Rails has a #blank? method – which I’ve used this weekend – but
nil.empty? is a false question.

-austin