From: Dark Ambient <sambient@...>
Date: 2006-08-14T06:12:11+09:00
Subject: Re: Search objects

That's a lot of food :)

Stuart

On 8/13/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> On Mon, 14 Aug 2006, Dark Ambient wrote:
>
> > I can use some help here:
> >
> > I've set up this class and objects and would like to "search" it
> > similar to the way I would search a database.  At this point I'm not
> > concerned with adding regex for more liberal searches.
> > Any suggestions ?
> >
> > class Composer
> >   def initialize( lname, country )
> >       @lname    = lname
> >       @country  = country
> >   end
> >       attr_accessor(:lname, :country)
> > end
> >
> > comp1 = Composer.new("Beethoven", "Germany")
> > comp2 = Composer.new("DeFalla", "Spain")
> > comp3 = Composer.new("Debussy", "France")
> >
>
> harp:~ > cat a.rb
> require 'weakref'
>
> class Composer
>    (ATTRIBUTES = %w( lname country )).each{|a| attr_accessor a}
>
>    INDEX = Hash.new{|h,k| h[k] = []}
>
>    def self.find arg
>      pattern =
>        case arg
>          when Hash
>            ATTRIBUTES.map{|a| arg[a] || arg[a.to_s] || arg[a.to_s.intern]}
>          when Array
>            arg
>          else
>            raise ArgumentError
>        end
>
>      n = pattern.size
>
>      keys = INDEX.keys.select do |key|
>        match = []
>        n.times do |i|
>          pat, k = pattern[i], key[i]
>          match <<
>            if pat.nil?
>              true
>            elsif pat.respond_to? 'call'
>              pat.call(k) ? true : false
>            elsif pat.respond_to? '==='
>              pat === k
>            elsif pat.respond_to? '=='
>              pat == k
>            else
>              false
>            end
>        end
>        match.all?
>      end
>
>      INDEX.values_at(*keys).map{|list| list.map{|weakref| weakref.__getobj__}}.flatten
>    end
>
>    def initialize *argv
>      ATTRIBUTES.each{|a| send "#{ a }=", argv.shift}
>      key = ATTRIBUTES.map{|a| send a}
>      val = WeakRef.new self
>      INDEX[key] << val
>    end
>
>    def to_hash
>      ATTRIBUTES.inject({}){|h,k| h.update k => send(k)}
>    end
>
>    def inspect
>      to_hash.inspect
>    end
>
>    def to_s
>      inspect
>    end
> end
>
> comp1 = Composer.new "Beethoven", "Germany"
> comp2 = Composer.new "DeFalla", "Spain"
> comp3 = Composer.new "Debussy", "France"
>
> found = Composer.find 'lname' => 'Beethoven'
> p found
>
> found = Composer.find 'lname' => %r/^bee|^defal/io
> p found
>
> found = Composer.find :country => lambda{|c| c.upcase === 'SPAIN'}
> p found
>
> class CaseOf < ::Array
>    def ===(other) flatten.compact.map{|pat| pat === other}.any? end
> end
> def caseof(*a, &b) CaseOf.new(*a, &b) end
>
> found = Composer.find :lname => %r/y$/, :country => caseof(%w[ Spain France ])
> p found
>
>
>
> harp:~ > ruby a.rb
> [{"country"=>"Germany", "lname"=>"Beethoven"}]
> [{"country"=>"Germany", "lname"=>"Beethoven"}, {"country"=>"Spain", "lname"=>"DeFalla"}]
> [{"country"=>"Spain", "lname"=>"DeFalla"}]
> [{"country"=>"France", "lname"=>"Debussy"}]
>
>
>
> food for thought.
>
> -a
> --
> to foster inner awareness, introspection, and reasoning is more efficient than
> meditation and prayer.
> - h.h. the 14th dali lama
>
>