Is there a way to store items in a hash, yet refer to them a

Rails
1

Hi,

Many of the view helpers require an object with accessor methods as
parameters.

There are times however, when I want to store a collection of
variables in a hash,
and yet be able to use these helpers.

Look at this example:
<%= text_area “person”, “description” %>
This works great for the case where I have a “person” object, with a
“description” attribute.
But what if I need to store the data in a hash, like this:
person[‘description’]
I don’t want to write a wrapper function to get all the hash values.
I would like to
use a gem or other builtin mechanism to be able to refer to
person.description -or-
person[‘description’]
interchangeably.

Is there a way to store variables in a collection (like a hash), and
use the keys of the
hash as accessor names in view helpers? Has anyone written one
already?

Thanks,

David

2

Hi David,

[email protected] wrote:

Is there a way to store variables in a collection
(like a hash), and use the keys of the hash as
accessor names in view helpers?

Cool idea.

Best regards,
Bill

3

This is dead simple and read-only, but how 'bout something like:

class HashyTest < Test::Unit::TestCase
def test_hashy_things
hash = HashWithIndifferentAccess.new

hash["monkeys"] = "These are monkeys."
hash["monkeys!"] = "Yes, monkeys!"
hash[:"monkeys?"] = "Do you like monkeys too?"

def hash.method_missing(sym, *args)
  self[sym]
end

assert_equal(hash["monkeys"], hash.monkeys)
assert_equal(hash["monkeys!"], hash.monkeys!)
assert_equal(hash[:"monkeys?"], hash.monkeys?)

end
end

~ j.

4

Hm. Might want to make this just slightly less confusing for methods
that don’t map to a key:

def hash.method_missing(sym, *args)
  include? sym and return self[sym]
  super
end

~ j.

5

John B. wrote:

def hash.method_missing(sym, *args)
self[sym]
end

Here’s a mildly destructive “Monkey Patch”, showing that technique to
avoid
writing too much attributes[‘blah’] all over the place.

class REXML::Element
def method_missing(symbol)
attr_name = symbol.id2name
attr_name.gsub!(/!$/, ‘’)

unless attributes.has_key?(attr_name)
  raise NoMethodError,
        "missing attribute: `#{attr_name}` in "+
          "<#{name} #{attributes.keys.join(' ')}>",
        caller
end
return attributes[attr_name]

end
end

Problem: It interferes with other Monkey Patches on REXML. (Too many
monkeys
climbing that inheritance tree!) I need to get around to seeing if blah?
would work better, for a clean read, and if the patch could call some
equivalent of ‘super’ would allow other monkey patches to pass thru.

Here’s its home project, a plugin, and its file:

http://phlip.svnrepository.com/svn/yar_wiki
http://phlip.svnrepository.com/svn/yar_wiki/lib/assert_xpath.rb

–
Phlip
"Pigleg too?", week 1