Rails - Aug 2005 - Symbols as Parameters

Hey all,

I''ve been staring at the pickaxe, experimenting, and looking through 
some of the Rails API but I can''t put this simple thing together.  I 
want to create a method that can have zero or more parameters and some 
of those are symbols.  A very simple example would look something like this:

find(options = {})
  if options[:unique]
    puts ''Do the unique operation''
  else
    puts ''Not-unique operation''
  end
end

And I want to be able to call this method as "find()" or 
"find(:unique)".  The above definition works fine if I do
"find()" or
"find(:unique => true)", but it barfs with just :unique. 
What''s the
right way to solve this?

Thanks!
- a very tired Jeff

Jeff,

Your method expects the "options" argument to be a Hash.
:unique is a symbol and symbols do not support the [] method.

find(:unique=>true) is a shortcut for find({:unique=>true}).
find(:unique=>true, :another_key=>false) is a shortcut for 
find({:unique=>true, :another_key=>false})

Note that only one argument is actually being passed (the Hash).

HTH,
Brian

On 8/21/05, Jeff Casimir <jeff-+RlNNtFrnNmT15sufhRIGw@public.gmane.org>
wrote:

Hey all,

I''ve been staring at the pickaxe, experimenting, and looking through
some of the Rails API but I can''t put this simple thing together. I
want to create a method that can have zero or more parameters and some
of those are symbols. A very simple example would look something like this:

find(options = {})
if options[:unique]
puts ''Do the unique operation''
else
puts ''Not-unique operation''
end
end

And I want to be able to call this method as "find()" or
"find(:unique)". The above definition works fine if I do
"find()" or
"find(:unique => true)", but it barfs with just :unique.
What''s the
right way to solve this?

Thanks!
- a very tired Jeff


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Hello Jeff,

Jeff Casimir said the following on 2005-08-22 01:52:
> find(options = {})
>  if options[:unique]
>    puts ''Do the unique operation''
>  else
>    puts ''Not-unique operation''
>  end
> end
> 
> And I want to be able to call this method as "find()" or 
> "find(:unique)".  The above definition works fine if I do
"find()" or
> "find(:unique => true)", but it barfs with just :unique. 
What''s the
> right way to solve this?
What you want should be this:
def find(options=nil)
   if :unique == options
     # unique operation
   else
     # non-unique operation
   end
end

As Brian said, you are expecting a Hash, not a single argument.  Above 
is what you want.  In fact, this method above can only accept ONE 
argument.  If you need more than one, you should do this instead:

def find(*options)
   if options.include?(:unique)
     # unique operation
   else
     # non-unique operation
   end
end

Hope that helps !
François