From: Dylan Evans <dylan.star@...>
Date: 2009-03-19T11:23:41+09:00
Subject: Re: Is this how you start a hash?

--0016e64f80b497955f04656f86b0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

On Thu, Mar 19, 2009 at 10:50 AM, Power One <arghx1@yahoo.com> wrote:

> I'm looking at the code below but still not clear about how this hash
> forms!  The author of a ruby book I read claimed that the code forms
> hash.  Is it?
>
> #not complete code, if you try to use it, it won't work!
>
> require 'yaml'
> require 'wordplay'
>
> class Bot
> attr_reader :name
>
> def initialize(options)
>  @name = options[:name] || "Unnamed Bot"
>  begin
>  @data = YAML.load(File.read(options[:data_file]))
>  rescue
>  raise "Can't load bot data"
>  end
> end
> end


Not sure what the author was getting at but YAML#load will probably return a
hash from the data file. The usage of options implies that a hash is passed
as an argument


>
>
> So, when you created hash, don't you have to initialize it with an empty
> hash?  For example:  @name = {}?


@name looks like it's supposed to be a string which is initialized from the
options hash, the || notation means that if options[:name] doesn't exist
then it will default to "Unnamed Bot".


>
>
> Also when I try to use a snippet in irb:
>  @name = options[:name] || "Unnamed Bot"
> NameError: undefined local variable or method `options' for main:Object
>  from (irb):1
>  from :0


You will need to initialize the hash in this case, or use variables, but it
might be best if your using irb to use constants such as;
@name = "Robocop"



>
>
> options is also in File.read(), it's acting like adding more element to
> a hash.  Am I right?  Though irb tells a different story as if it's not
> how you starting a hash.


No it's not adding elements to the options hash, it is reading them. That
line returns a hash to @data (which is probably the one you want) based on
the contents of the file referred to by options[:data_file].



>
>
> I'm confused!


Aren't we all?


>
> --
> Posted via http://www.ruby-forum.com/.
>
>


-- 
The UNIX system has a command, nice ... in order to be nice to the other
users. Nobody ever uses it." - Andrew S. Tanenbaum

--0016e64f80b497955f04656f86b0--