From: Daniel Sheppard <daniels@...>
Date: 2005-10-28T14:42:52+09:00
Subject: Re: "Reflecting" on my self.n00b

There's two ways you can go depending on if you want to be able to add
attributes that are NOT stored.

The easiest way is to use attr_accessor:

class ServiceProfile
    attr_accessor :url, :username, :password, :certificate, :owner
    def load_certificate()
        @certificate.read
    end
    def call_service(&block)
    end
end

class MyService < ServiceProfile
    attr_accessor :extra
end

svc_profile = MyService.new

svc_profile.methods.sort.reverse.each { |meth|
    if /^(.*)=$/ === meth
        print "Enter #{$1.capitalize}: "
        $stdout.flush
        value = $stdin.gets.chomp
        svc_profile.send(meth, value)
    end
}

svc_profile.methods.sort.reverse.each { |meth|
    if /^(.*)=$/ === meth
        puts svc_profile.send($1)
    end
}

The problem with this, however, is that you can't add any xxx=(x)
methods to the class without them being added to your storage system.
Instead, you could do:

class AutoPopulator
    def self.attr_populator(*args)
        attr_accessor(*args)
        (@populators||=[]).concat(args)
    end
    def self.populators
        populators = []
        populators = superclass.populators if superclass.respond_to?
:populators
        populators += @populators if @populators
        populators.uniq.collect {|x| x.to_s}
    end
end

class ServiceProfile < AutoPopulator
    attr_populator :url, :username, :password, :certificate, :owner
    def load_certificate()
        @certificate.read
    end
    def call_service(&block)
    end
end

class MyService < ServiceProfile
    attr_populator :extra
end

svc_profile = MyService.new

svc_profile.class.populators.each { |meth|
    print "Enter #{meth.capitalize}: "
    $stdout.flush
    value = $stdin.gets.chomp
    svc_profile.send("#{meth}=", value)
}

svc_profile.class.populators.each { |meth|
    puts svc_profile.send(meth)
}
   

> -----Original Message-----
> From: wmwilson01@gmail.com [mailto:wmwilson01@gmail.com] On 
> Behalf Of swille
> Sent: Friday, 28 October 2005 11:11 AM
> To: ruby-talk ML
> Subject: "Reflecting" on my self.n00b
> 
> I'm admittedly quite a novice with programming.  I'm sort of 
> playing around with some ideas, and I'm wondering if what I'm 
> doing is completely stupid, and if not, is there a better way 
> to do it?  Also, is there any way that I could do some type 
> of type-ish validation on the data?
> 
> Basically, I want to provide what I suppose would be abstract 
> class (?), which someone else could extend and add attributes 
> if they'd like.  I'd like to be able to look into the class 
> and pick out the attributes to populate (which is the reason 
> for all of the sp_set & sp_get stuff).  Basically, my thought 
> is to be able to provide a web interface at some point to 
> populate the needed data of a class, and then maybe 
> Marshal.dump the object to a database and call it later using 
> that data as config data essentially.  I'm sure I could learn 
> a ton about this from reading Rails code, but there's so much 
> of it that I don't know where to look.  Output and code 
> follows.  Please feel free to tell me if this is dumb :O)
> 
> Output:
> Enter Username: name
> Enter Url: url
> Enter Extra: more
> Enter Password: pass
> Enter Owner: own
> Enter Certificate: cert
> name
> url
> more
> pass
> own
> cert
> 
> Code:
> <code>
> class ServiceProfile
>     def  initialize()
>     end
> 
>     def sp_set_url(url)
>         @url = url
>     end
> 
>     def  sp_get_url()
>         @url
>     end
> 
>     def sp_set_username(username)
>         @username = username
>     end
> 
>     def  sp_get_username()
>         @username
>     end
> 
>     def sp_set_password(password)
>         @password = password
>     end
> 
>     def sp_get_password()
>         @password
>     end
> 
>     def sp_set_certificate(certificate)
>         @certificate = certificate
>     end
> 
>     def  sp_get_certificate()
>         @certificate
>     end
> 
>     def sp_set_owner(owner)
>         @owner = owner
>     end
> 
>     def  sp_get_owner()
>         @owner
>     end
> 
>     def load_certificate()
>         @certificate.read
>     end
> 
>     def call_service(&block)
>     end
> end
> 
> class MyService < ServiceProfile
>     def sp_set_extra(extra)
>         @extra = extra
>     end
> 
>     def sp_get_extra()
>         @extra
>     end
> end
> 
> svc_profile = MyService.new
> 
> set_re = Regexp.new('^sp_set_(\w+)')
> get_re = Regexp.new('^sp_get_(\w+)')
> 
> svc_profile.methods.sort.reverse.each { |meth|
>     if meth.match(set_re)
>         print "Enter #{Regexp.last_match(1).capitalize}: "
>         value = $stdin.gets.chomp
>         svc_profile.send(meth, value)
>     end
> }
> 
> svc_profile.methods.sort.reverse.each { |meth|
>     if meth.match(get_re)
>         puts svc_profile.send(meth)
>     end
> }
> </code>
> 
> 
> 
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