From: Joel VanderWerf <vjoel@...>
Date: 2003-01-27T19:56:32+09:00
Subject: Re: cascading configuration variables

Gavin Sinclair wrote:
> On Monday, January 27, 2003, 2:15:38 AM, Wilbert wrote:
> 
> 
>>a little follow-up on loading config data as Ruby source files. I
>>want my project to load some full system defaults from a file, and
>>then some user-specified overrides from another file, and finally
>>some special overrides that are set on the commandline or from the
>>calling environment.
> 
> 
> I think there's an RAA package called PseudoHash or something that
> allows chaining hashes to retrieve different values (system, user,
> default, etc.).

PseudoHash appears to be an ordered hash.

SuperHash allows chains of hashes which inherit key-value pairs. This 
might be useful if you need to reuse, say, the system defaults several 
times during the program (maybe for different users). But Hash#update 
might serve just as well. The main difference is that SuperHash is 
dynamic (changing system options would affect all users, existing and 
future) whereas Hash#update is static (changing system options would 
only affect users generated after the change).