From: Michael Edgar <adgar@...>
Date: 2011-06-21T03:17:51+09:00
Subject: Re: What about Object#to_ruby ?

On Jun 20, 2011, at 2:02 PM, Bernard Lambeau wrote:

> Thanks a lot for your responses. I suspect that my question was not that
> clear, though.
> 
> I'm not really looking or Marshal or YAML or JSON dump format, but for a
> method
> to print a ruby *literal* (I should have called it to_ruby_literal) from a
> ruby value,
> where it makes sense. The goal is to ease human-readable ruby code
> generation,
> I must add. Nowadays, using inspect works for all but a few basic values:


It sounds like you're essentially talking about a marshal format that *is*
Ruby code.

Something along the lines of this, without procs, singleton classes, no
cyclic references (ruby 1.9), etc:

class Object
  def to_ruby_literal
    str = "#{self.class.name}.allocate.tap do |obj|\n"
    instance_variables.each do |ivar|
      str << "obj.instance_variable_set(#{ivar}, #{instance_variable_get(ivar).to_ruby_literal})\n"
    end
    str << "end"
  end
end

[TrueClass, FalseClass, NilClass, String, Integer, Float].each do |klass|
  klass.class_eval do
    alias_method :to_ruby_literal, :inspect
  end
end

Usage:

class A
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
end
puts A.new(1.3, "hello", false).to_ruby_literal

A.allocate.tap do |obj|
obj.instance_variable_set(@x, 1.3)
obj.instance_variable_set(@y, "hello")
obj.instance_variable_set(@z, false)
end

Michael Edgar
adgar@carboni.ca
http://carboni.ca/