Comments on: Quiz

By: Try() as you might | Lambda @ Copa

Try() as you might | Lambda @ Copa — Sun, 11 Jan 2009 12:43:18 +0000

[...] I came across a few other alternatives that were entertaining the idea of using method_missing, but let’s [...]

By: Aaron Feng : Learning from io

Aaron Feng : Learning from io — Thu, 25 Sep 2008 03:18:13 +0000

[...] The above code is taken from this post The post didn't mention io, but I assumed it is inspired by it. In ruby you can't just use the "?" for your method name, therefore, _ is prepended before "?".Now you can do following without checking the parent object: offer.?.price.?.formatted_amount [...]

By: trapdoor1 » Object.too_clever_by_half? rescue nil

trapdoor1 » Object.too_clever_by_half? rescue nil — Sat, 05 Apr 2008 13:07:38 +0000

[...] Monkey-patching proposals have abounded in the Ruby community recently - including, but not limited to Object#andand, Object#? and SafeNil and Object#method. [...]

By: Tyler Rick

Tyler Rick — Fri, 12 Oct 2007 11:08:08 +0000

This is awesome! I've been wanting something like this for ages.

I hope you don't mind, I've added it to the quality_extensions gem on RubyForge. (rdoc source)

Hopefully we can get this included in Facets too so an even wider group of people can enjoy it!

By: Tom

Tom — Tue, 02 Oct 2007 18:10:12 +0000

Coda -- all of your examples have one thing in commen that this operator was specifically intended to avoid. string_or_nil occurs twice.

The places where I use _? are where I don't have the value in a local variable, and I don't want to assign it to one just because I have an operation to perform "only if the value is not nil". e.g.

if Foo.expensive_method_call._?.closed?
  ...

I see this pattern all the time in my code and I really enjoy not having to make the code more verbose. To me this reads like a spec, once you've internalised the simple _? operator.

By: Coda Hale

Coda Hale — Tue, 02 Oct 2007 17:45:02 +0000

Why not just use single-line conditionals?

x = string_or_nil.length unless string_or_nil.nil?
x #=> nil

Or, if you're looking for compound conditions:

if (not string_or_nil.nil?) && (string_or_nil.length == 4)

This seems like a fair bit of cleverness to avoid making your guard conditions explicit -- which seems to me like it could make maintenance more of a pain than it already is.

Also, unlike the ternary operator, this doesn't allow you to specify a fallback value without using || or some other comparison. Why not this:

x = (string_or_nil && string_or_nil.length) || 6

Other than that, cool Ruby trick.

By: The Ternary Destroyer « coderrr

The Ternary Destroyer « coderrr — Sat, 15 Sep 2007 18:30:45 +0000

[...] The Ternary Destroyer Filed under: Uncategorized — coderrr @ 6:59 pm I just ran across this Hobo blog post which describes an awesome way to get rid of a lot of use cases for the ternary operator. [...]

By: steve d

steve d — Sat, 15 Sep 2007 18:26:28 +0000

2000% speed increase if you define SafeNil this way:

class SafeNil
  def method_missing(method, *args, &b)
    return nil  unless nil.respond_to? method
    nil.send(method, *args, &b) rescue nil
  end
end

Only problem with this way would be if you define methodmissing on nil to route method calls to it, because then respondto? wouldn't be accurate

By: steve d

steve d — Sat, 15 Sep 2007 17:26:02 +0000

Awesome! very useful!

By: Ryan Allen

Ryan Allen — Mon, 10 Sep 2007 01:13:45 +0000

Good in loose views for missing methods? I dunno. SafeNil makes me nervous…