From: Kent Sibilev <ksibilev@...>
Date: 2004-03-13T04:48:40+09:00
Subject: Re: Win32OLE bug

Yes, it seems that WIN32OLE library doesn't mix-in Enumerable module 
into its collections.
This would work:

forms = $iec.document.forms
forms.extend(Enumerable)
forms.find{|f| f.action == 'start'}

According to PickAxe 
http://rubycentral.com/book/tut_expressions.html#UK the only difference 
between 'for..in' and 'each' forms of iteration is the scope of local 
variables defined in the iteration block.

/kent.

On Mar 12, 2004, at 1:58 PM, Bret Pettichord wrote:
> Thanks Chad. I actually included my workaround in my original post 
> (but which kent snipped). I don't understand what you have here. 
> Here's my original workaround:
>
> def get_form_by_action(action)
>   "Return the first Form on the current page that has the specified 
> Action."
>   retval = nil # this ugliness avoids scripts hanging on exit (1.6) or 
> a LocalJumpError (1.8)
>   for form in @iec.document.forms
>     next if retval
>     if form.action == action
>       retval = IEDomFormWrapper.new(form)
>     end
>   end
>   return retval
> end
>
>
> Here is what i really want to do:
>
> irb(main):036:0> $iec.document.forms.find {|f| f.action == "start" }
> WIN32OLERuntimeError: Unknown property or method : `find'
>     HRESULT error code:0x80020006
>       Unknown name
>         from (irb):36:in `method_missing'
>         from (irb):36
>         from ?:0
>
> forms is an OLE collection object, so it supports each, but apparently 
> doesn't have Enumerable mixed in. Can i mix this in on my own? Should 
> i be expecting this to be done by the WIN32OLE library?
>
> Here's my latest rewrite, which works, and is easier for me to 
> understand and explain than the one you gave Chad. (I don't know what 
> callcc does. Continuations? I'll leave that for another day.)
>
> def get_form_by_action(action)
>   "Return the first Form on the current page that has the specified 
> Action."
>   for form in @iec.document.forms
>     break if form.action == action
>   end
>   IEDomFormWrapper.new(form)
> end
>
> I did try the following, but was surprised to see that it didn't work, 
> since i thought that this was supposed to be the same as the previous 
> but more the ruby way.
>
> def get_form_by_action(action)
>   "Return the first Form on the current page that has the specified 
> Action."
>   @iec.document.forms.each do | form |
>     break if form.action == action
>   end
>   IEDomFormWrapper.new(form)
> end
>
> This give this error:
>
> irb(main):044:0> get_form_by_action("start")
> NameError: undefined local variable or method `form' for 
> #<Object:0x100f9480>
>         from ./toolkit/iec-assist.rb:39:in `get_form_by_action'
>         from (irb):44
>         from ./toolkit/iec-assist.rb:2
>
> To correct, i need to explicitly change the scope of the bound 
> variable:
>
> def get_form_by_action(action)
>   "Return the first Form on the current page that has the specified 
> Action."
>   form = nil
>   @iec.document.forms.each do | form |
>     break if form.action == action
>   end
>   IEDomFormWrapper.new(form)
> end
>
> As you may know i am preparing to teach novices to use Ruby, and i 
> can't quite think of how i can teach them why these two forms are 
> different. It would be much easier for me to be able to say they are 
> the same. (Between you and me, i see that the scope of the bound 
> variable is different between the for-in and each forms. But this 
> means that the difference is more than just syntactic sugar.)
>
> So, am i still confused somewhere? Is it supposed to be this way? (I'm 
> using 1.8.0.)
>
> Is there a way i can get forms.find to work directly?
>
> Bret
>
> ______________________________________
>  Bret Pettichord, Software Tester
>    Consultant - www.pettichord.com
>    Author - www.testinglessons.com
>    Blogger - www.io.com/~wazmo/blog
>
>    Homebrew Automation Seminars
>    March 19, Redmond, Washington
>    April 30, Austin, Texas
>    www.pettichord.com/training.html
>
>


Cheers,
Kent.