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Groups > comp.lang.ruby > #3025

Making a simple parser

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Hi all,

To automate some of the tests I have to run, I decided to use ruby to
generate some script files on a particular (very simple) language based
on several possible input files. My first approach at this was to use
inherited method on a parent class (which I called InputFormat) to hold
all the children in an array. Then, different formats could become a
child class of InputFormat and return a known data format (I decided to
use an array of hashes because the output is really really simple) to
the output generator code.

So the idea is something like:

class InputFormat
  @children = []

  def initialize(input)
    @input = input
  end

  def parse
    @children.each { |child|
      child.parse(@input) if child.supported?(@input)
    }
  end

  def self.inherited(child)
    @children << child
  end
end

class AInputFormat < InputFormat
  def supported?
    # check if we can parse this type of file
  end

  def parse
    # parse and generate array of hashes in known format
  end
end


Then on the core file I would have something like:

input = InputFormat.new(ARGV[0])
input.parse

As it turns out, this isn't working because AInputFormat will only
inherit from InputFormat at the time I actually use it, am I right ? Any
tips you guys could give me to achieve what I want ? (from several
possible input formats generate one output format)

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

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Thread

Making a simple parser Felipe Balbi <balbif@gmail.com> - 2011-04-16 14:52 -0500
  Re: Making a simple parser 7stud -- <bbxx789_05ss@yahoo.com> - 2011-04-16 22:31 -0500
  Re: Making a simple parser jake kaiden <jakekaiden@yahoo.com> - 2011-04-17 12:01 -0500
    Re: Making a simple parser Felipe Balbi <balbif@gmail.com> - 2011-04-17 15:22 -0500
      Re: Making a simple parser jake kaiden <jakekaiden@yahoo.com> - 2011-04-17 21:10 -0500
  Re: Making a simple parser Jesús Gabriel y Galán <jgabrielygalan@gmail.com> - 2011-04-18 02:22 -0500
    Re: Making a simple parser Felipe Balbi <balbif@gmail.com> - 2011-04-19 16:03 -0500
  Re: Making a simple parser 7stud -- <bbxx789_05ss@yahoo.com> - 2011-04-18 13:24 -0500
    Re: Making a simple parser 7stud -- <bbxx789_05ss@yahoo.com> - 2011-04-18 15:22 -0500

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