From: Daniel Martin <martin@...>
Date: 2007-08-19T22:45:57+09:00
Subject: Re: YAML and NArray

Daniel Martin <martin@snowplow.org> writes:

> So anyway, I finally integrated YAML and NArray, and present the
> solution here for other people googling in the future on how to get
> these two to work together, as well as now for comment and criticism
> by current list subscribers.  Note that it handles NArray, NMatrix,
> and NVector objects:

And this is what I get for posting something other than the exact code
I tested with.  Apparently there's a bug in Syck such that email-based
tags are treated differently from dns-based tags.  Unfortunately, I
don't own a domain name - fortunately, I know the guy who does own
snowplow.org, and I'm pretty sure he'd be okay with me using the tag
prefix shown below.

So here's a fixed version.  Note that it is the same as before, except
that the private tag used in the yaml_as line is different.

########## narray-yaml.rb #########
require 'yaml'
require 'narray'

# First, a yaml utility routine to make the output prettier

module YAML
  class YIArray < Array
    yaml_as "tag:yaml.org,2002:seq"
    def to_yaml_style; :inline; end
  end

  def YAML.inline_array(arr)
    if Array === arr[0] then
      arr.map {|s| inline_array(s)}
    else
      YIArray.new.concat(arr)
    end
  end
end

class NArray
  # I used a tag of my own since I wasn't sure if
  # someone else had their own serialization of
  # NArray objects
  yaml_as "tag:snowplow.org,2007:martin/narray"
  def to_yaml( opts = {} )
    YAML::quick_emit( self.object_id, opts ) do |out|
      out.map(taguri) do |map|
        map.add('typecode', typecode)
        map.add('shape', YAML::inline_array(shape))
        map.add('data', YAML::inline_array(to_a))
      end
    end
  end

  def self.yaml_new(klass, tag, val)
    result = klass.new(val['typecode'], *(val['shape']))
    result[] = val['data']
    result
  end
end
__END__

Hopefully this message will be found by people googling for how to
integrate YAML and NArray.

I'm going to make this file available at
http://snowplow.org/martin/narray/

along with standard verbiage up at the top placing it under some
variant of the MIT license or the no-attribution BSD license.

-- 
s=%q(  Daniel Martin -- martin@snowplow.org
       puts "s=%q(#{s})",s.to_a.last       )
       puts "s=%q(#{s})",s.to_a.last