From: mortee <mortee.lists@...>
Date: 2007-10-11T21:32:12+09:00
Subject: Re: Using strings to drill down into objects

Ross X Dawson wrote:
>     # lambda function to drill down object hierarchy
>     drill_down = lambda do |obj, method_name|
>                           o ||= obj
>                           method_name.split('.').each {|m| o = o.send(m) if
> o.respond_to?(m)}
>                           o
>                   end
> 
> methods = ['lookup1.code', 'lookup1.name']
> 
> report_value = drill_down.call(my_object_with_lookups, methods)

I'm not sure what your intent is, but I guess this code won't work.

First, unless you define it before creating the lambda, "o" won't exist
in its binding, so you can't call o ||= obj. Second, you pass an array
of method names to your lambda as a second parameter, on which #split
isn't defined.

You could state instead:

method_name.each{|name| name.split{|part| ... } }

but then, "part" would take the value "lookup1", "code", "lookup1"
again, and "name" in that order. I highly doubt you want this.

However, AFAIK you're right that o.send(m, *args) is the way to call an
arbitrary named method on an object.

mortee