From: Robert Klemme <shortcutter@...>
Date: 2007-11-26T04:45:08+09:00
Subject: Re: Supplying multiple procs to initialization

On 25.11.2007 19:36, Phrogz wrote:
> One of my libraries previously required code like this:
> 
>   # Convert markup to HTML, doing something
>   # useless with links and commands
>   owl = OWLScribble.new( markup )
>   owl.wiki_links.each{ |link|
>     # do something useful to the link
>   }
>   owl.wiki_commands.each{ |command|
>     # do something useful with the command
>   }
>   html = owl.to_html
> 
> I have changed it so that the user can instead describe how to handle
> links and commands in general, so that during initialization the
> library doesn't waste time or code lines doing something useless:
> 
>   owl = OWLScribble.new( markup ) do |owl|
>     owl.handle_wiki_link do |tag, page, link_text|
>       # do something useful to the link
>     end
>     owl.handle_wiki_command do |tag, command, params|
>       # do something useful to the command
>     end
>   end
>   puts owl.to_html
> 
> The syntax you see above is my current favorite choice for specifying
> these two procs. Alternatives that I have rejected as less elegant:
> 
>   # Deferred initialization
>   owl = OWLScribble.new( markup )
>   owl.handle_wiki_link{ ... }
>   owl.handle_wiki_command{ ... }
>   owl.run
>   puts owl.to_html
> 
>   # proc params
>   do_link = proc{ ... }
>   do_command = proc{ ... }
>   owl = OWLScribble.new(
>     markup,
>     :handle_wiki_link=>do_link,
>     :handle_wiki_command=>do_command
>   )
>   puts owl.to_html
> 
> Can anyone suggest a more elegant way of supplying multiple processing
> procs that should be used during initialization, on a per-instance
> basis?

Why not just

   owl = OWLScribble.new(
     markup,
     :handle_wiki_link => lambda {...},
     :handle_wiki_command => lambda {...}
   )

Kind regards

	robert