From: Jim Freeze <jim@...>
Date: 2005-09-10T03:34:40+09:00
Subject: Re: [QUIZ] NDiff (#46)

Hi

To help the quiz writers focus on the 'the quiz' and not the administrative
part of the code and to help promote CommandLine, here is a little snippet
that some may find useful to get started.

#!/usr/bin/env ruby

require 'rubygems'
require 'commandline'

class NDiffApp < CommandLine::Application
  def initialize
    author "Jim Freeze"
    copyright "2005 Jim Freeze"
    synopsis "[-hqs] [-d INT] [-t DBL] file1 file2"
    short_description "Numerically compare files line by line, "+
                      "numerical field by numerical field."

    option :names           => %w(--digits -d),
           :opt_description => "Maximum number of significant digits that "+
                               "should match. (default: 0)",
           :arg_description => "INT",
           :opt_found       => get_arg,
           :opt_not_found   => "0"

    option :names           => %w(--tolerance -t),
           :opt_description => "Tolerate <= DBL distance between numbers. "+
                               "(default: 0.0)",
           :arg_description => "DBL",
           :opt_found       => get_arg,
           :opt_not_found   => "0.0"

    option :flag,
           :names           => %w(--statistics -s),
           :opt_description => "Provide comparison statistics only.
(extra credit)"

    option :flag,
           :names           => %w(--quiet -q),
           :opt_description => "No output printed to screen. just exit code.??"

    option :help

    expected_args :file1, :file2
  end

  def main
    NDiff.new(@file1, @file2, 
      @option_data["--digits"].to_i,
      @option_data["--tolerance"].to_f,
      @option_data["--statistics"],
      @option_data["--quiet"])
  end

end#class NDiffApp

class NDiff
  # Your code here
  def initialize(file1, file2, 
    digits=0, 
    tolerance=0.0, 
    statistics=false, 
    quiet=false)

    p file1
    p file2
    p digits
    p tolerance
    p statistics
    p quiet
  end

end#class NDiff

The printout is quit nice, and it takes no extr effort:

% ./ndiff 
 Usage: ndiff [-hqs] [-d INT] [-t DBL] file1 file2
% ./ndiff file1
ERROR: Missing expected arguments. Found 1 but expected 2.
 Usage: ndiff [-hqs] [-d INT] [-t DBL] file1 file2
% ./ndiff -h
NAME

    ndiff - Numerically compare files line by line, numerical field by
    numerical field.

SYNOPSIS

    ndiff [-hqs] [-d INT] [-t DBL] file1 file2

OPTIONS

    --digits,-d INT
        Maximum number of significant digits that should match.
        (default: 0)

    --tolerance,-t DBL
        Tolerate <= DBL distance between numbers. (default: 0.0)

    --statistics,-s
        Provide comparison statistics only. (extra credit)

    --quiet,-q
        No output printed to screen. just exit code.??

    --help,-h
        Displays help page.

AUTHOR:  Jim Freeze
COPYRIGHT (c) 2005 Jim Freeze

A little note, I did not understand "just exit code" for -q. What is
'-q' supposed
to do. No output at all?

It also appears that the ability to type cast input to floats or ints or
whatever should be added to CommandLine. All comments are appreciated.

-- 
Jim Freeze