[#154598] implementing the "each" method for own classes — Philipp Huber <huber.philipp@...>

hello!

12 messages 2005/09/01

[#154620] Word Chains (#44) — Ruby Quiz <james@...>

Gavin Kistner asked that I try timing the quiz solutions this week. I did

13 messages 2005/09/01

[#154733] Ruby-specific performance heuristics? — Hugh Sasse <hgs@...>

I've been doing some stuff with CSV recently, having data in one

15 messages 2005/09/02

[#154775] Idiomatic conversion of yielding block to array — David Brady <ruby_talk@...>

So I have a function that generates like 300 lines of text and I want to

23 messages 2005/09/02
[#154776] Re: Idiomatic conversion of yielding block to array — Levin Alexander <levin.alexander@...> 2005/09/02

David Brady <ruby_talk@shinybit.com> wrote:

[#154779] Re: Idiomatic conversion of yielding block to array — Simon Krer <SimonKroeger@...> 2005/09/02

Levin Alexander wrote:

[#154785] Re: Idiomatic conversion of yielding block to array — Simon Krer <SimonKroeger@...> 2005/09/02

Simon Krer wrote:

[#154789] Re: Idiomatic conversion of yielding block to array — Jacob Fugal <lukfugl@...> 2005/09/02

Good heavens, no! Neither of those are thread safe. Criminy!

[#154872] windows shell — Gaston Garcia <gaston.garcia@...>

Is there anyone here that uses Windows XP and uses a windows shell

28 messages 2005/09/04
[#154876] Re: windows shell — "Robert Klemme" <bob.news@...> 2005/09/04

Gaston Garcia <gaston.garcia@gmail.com> wrote:

[#154917] Re: windows shell — Austin Ziegler <halostatue@...> 2005/09/05

On 9/4/05, Robert Klemme <bob.news@gmx.net> wrote:

[#154874] params v.s. @params in rails? — "Barry" <rubyrails@...>

Both work in my controller class, so I am wondering what's the

11 messages 2005/09/04

[#154920] Help me clean up this method — "Vincent Foley" <vfoley@...>

Hello guys,

32 messages 2005/09/05

[#155018] Rake 0.6.0 Released — Jim Weirich <jim@...>

= Rake 0.6.0 Released

20 messages 2005/09/06

[#155064] Sorted arrays — <ruby@...64.com>

I'm a relative newcomer to Ruby. Most of my experience is in Delphi. And in Delphi one of the most commonly-used classes is TStringList, which is sort of analogous to ruby's Array (Delphi also has dynamic arrays and static arrays). TStringList has a property called Sorted, which if set to True makes it possible to insert strings into the list and have it maintain them as a sorted list (without having to re-sort it each time). Then you can use the IndexOf method (or the Find method) to do a binary search on the list, so you can quickly find the element you're looking for. My question is whether Ruby has anything like this. It seems like one could create a descendant of Array that does this.

18 messages 2005/09/06
[#155067] Re: Sorted arrays — "Robert Klemme" <bob.news@...> 2005/09/06

ruby@danb64.com wrote:

[#155120] Units for Ruby — "Lucas Carlson" <lucas@...>

I have also created a new library to add units to numbers in Ruby:

14 messages 2005/09/06

[#155127] Rio 0.3.4 — "rio4ruby" <rio4ruby@...>

New and Improved -- Rio 0.3.4

24 messages 2005/09/07

[#155181] Need help finding decent IDE/development environment for Windows — "Paul Dix" <paulcdix@...>

I've just started playing around with ruby on rails and by association,

41 messages 2005/09/07
[#155218] Re: Need help finding decent IDE/development environment for Windows — graham <fghfghfh@...> 2005/09/07

Paul Dix wrote:

[#155220] Re: Need help finding decent IDE/development environment for Windows — Joe Van Dyk <joevandyk@...> 2005/09/07

On 9/7/05, graham <fghfghfh@homr.vom> wrote:

[#155221] Re: Need help finding decent IDE/development environment for Windows — graham <fghfghfh@...> 2005/09/07

> You could ask them why they need all that IDE stuff for developing in Ruby.

[#155225] Re: Need help finding decent IDE/development environment for Windows — Edward Faulkner <ef@...> 2005/09/07

On Thu, Sep 08, 2005 at 02:36:29AM +0900, graham wrote:

[#155264] Re: Need help finding decent IDE/development environment for Windows — graham <fghfghfh@...> 2005/09/07

Edward Faulkner wrote:

[#155280] Re: Need help finding decent IDE/development environment for Windows — James Edward Gray II <james@...> 2005/09/08

On Sep 7, 2005, at 6:56 PM, graham wrote:

[#155327] general performance question — Brian Le Roy <brian@...>

I'm running top and when I run my app - I see the user CPU utilitization

15 messages 2005/09/08

[#155364] KirbyBase — rubyhacker@...

I'm posting from work, but will try to follow up in more

57 messages 2005/09/08
[#155795] Re: KirbyBase — rubyhacker@... 2005/09/12

Jamey Cribbs wrote:

[#155801] Re: KirbyBase — Jamey Cribbs <cribbsj@...> 2005/09/12

rubyhacker@gmail.com wrote:

[#155818] Re: KirbyBase — Randy Kramer <rhkramer@...> 2005/09/12

On Monday 12 September 2005 04:11 pm, Jamey Cribbs wrote:

[#155833] Re: KirbyBase — rubyhacker@... 2005/09/12

Randy Kramer wrote:

[#155836] Re: KirbyBase — Kevin Brown <blargity@...> 2005/09/12

On Monday 12 September 2005 17:06, rubyhacker@gmail.com wrote:

[#155861] Re: KirbyBase — Hal Fulton <hal9000@...> 2005/09/13

Kevin Brown wrote:

[#155873] Re: KirbyBase — Ezra Zygmuntowicz <ezra@...> 2005/09/13

[#155976] Re: KirbyBase — rubyhacker@... 2005/09/13

[#155986] Re: KirbyBase — Jamey Cribbs <cribbsj@...> 2005/09/13

rubyhacker@gmail.com wrote:

[#156005] Re: KirbyBase — Logan Capaldo <logancapaldo@...> 2005/09/13

[#156029] Re: KirbyBase [ANN (sort-of)] proof-of-concept KirbyBase ORM — Logan Capaldo <logancapaldo@...> 2005/09/14

[#155369] compiling ruby on red hat linux — "Philip J. Mikal" <philip_mikal@...>

Hi,

15 messages 2005/09/08

[#155411] Optimizing a single slow method — "Glenn M. Lewis" <noSpam@...>

Hi!

34 messages 2005/09/09
[#155474] Re: Optimizing a single slow method — Eric Hodel <drbrain@...7.net> 2005/09/09

On 08 Sep 2005, at 20:46, Glenn M. Lewis wrote:

[#155464] quick print type debugging — Eric Mahurin <eric_mahurin@...>

Anybody think something like this would be useful?

12 messages 2005/09/09

[#155507] Using Ruby as a preprocessor for another language — debbie@...

I have the misfortune of being stuck programming in a very bad

11 messages 2005/09/10

[#155530] Win32 gem for RMagick 1.9.1 — Timothy Hunter <cyclists@...>

Hot on the heels of the latest RMagick update, Kaspar Schiess has

15 messages 2005/09/10

[#155537] RCR to modify #puts and #print inside ERB — Gavin Kistner <gavin@...>

Proposed RCR:

26 messages 2005/09/10

[#155601] r4 - the simplest ruby pre-processor — "Ara.T.Howard" <Ara.T.Howard@...>

18 messages 2005/09/11

[#155638] The Early Demise of Myriad (Thanks To Ruby Threads) — "Zed A. Shaw" <zedshaw@...>

Hi Everyone,

17 messages 2005/09/11

[#155708] how to well-qualify the 2-inherited methods at their collision point — "SHIGETOMI, Takuhiko" <tshiget1@...>

dear guys,

10 messages 2005/09/12

[#155828] Adventures in html decoding. — Morgan <taria@...>

From the "If you want it done right, do it yourself... maybe"

16 messages 2005/09/12

[#155847] Choosing an open source license — "debbie@..." <debbie@...>

I'm working on a server program and I'm trying to decide which open

22 messages 2005/09/13

[#155941] yet another simple command-line option parser — Eric Mahurin <eric_mahurin@...>

I just put in a good example for:

11 messages 2005/09/13
[#155946] Re: yet another simple command-line option parser — Jim Freeze <jim@...> 2005/09/13

That's pretty interesting Eric, to grab the type off the default.

[#155949] Sets, uniqueness not unique. — Hugh Sasse <hgs@...>

I have been splitting a comma separated values file, and putting

29 messages 2005/09/13

[#155970] Surprising Regexp Behavior — James Edward Gray II <james@...>

I keep running into some surprising points with Ruby's Regexp engine

13 messages 2005/09/13

[#155992] Launch directory in Rake — Jim Freeze <jim@...>

Hi

15 messages 2005/09/13

[#156053] ruby and aop — Alexandru Popescu <the.mindstorm.mailinglist@...>

Hi!

12 messages 2005/09/14

[#156189] Get to the Point: Ruby and Rails Presentation Slides — "John W. Long" <ng@...>

Hi,

20 messages 2005/09/15

[#156230] you can't get in trouble with your boss for picking C# — "Phlip" <phlipcpp@...>

Rubies:

69 messages 2005/09/15
[#156549] Re: you can't get in trouble with your boss for picking C# — "ToRA" <tristan.allwood@...> 2005/09/17

Hey all,

[#156582] Re: you can't get in trouble with your boss for picking C# — Florian Gro<florgro@...> 2005/09/18

ToRA wrote:

[#156297] Re: you can't get in trouble with your boss for picking C# — "Phlip" <phlipcpp@...> 2005/09/15

klancaster1957 wrote:

[#156308] Re: you can't get in trouble with your boss for picking C# — Josh Charles <josh.charles@...> 2005/09/15

On 9/15/05, Phlip <phlipcpp@yahoo.com> wrote:

[#156248] Math: sum and faculty — Daniel Schierbeck <daniel.schierbeck@...>

I hereby propose two additions to Ruby. Please come with some comments

13 messages 2005/09/15

[#156299] MS Access — "Steve" <sdouglas949@...>

I'm considering learning Ruby. I have no programming experience yet. I was

23 messages 2005/09/15
[#156303] Re: MS Access — "Phlip" <phlipcpp@...> 2005/09/15

Steve wrote:

[#156335] Re: MS Access — Sean Armstrong <phinsxiii@...> 2005/09/15

On 9/15/05, Phlip <phlipcpp@yahoo.com> wrote:

[#156336] Re: MS Access — Sascha Ebach <se@...> 2005/09/15

Sean Armstrong wrote:

[#156347] Re: MS Access — Sean Armstrong <phinsxiii@...> 2005/09/15

Does anyone know how to install the Ruby MySQL module on a Windows platform.

[#156352] Re: MS Access — Jacob Quinn Shenker <jqshenker@...> 2005/09/15

Sean,I needed to compile/install mysql (running ./configure--without-server) from source to get the required developmentlibraries under Cygwin. (then I moved the newly-created clientbinaries out of the way so I could use the Win32-native mysqlbinaries.) After that, it worked like a charm. *Do not compile theCygwin-ized mysql client with "--with-openssl"* I don't know why, butthe gem refused to install if I did. Good luck, and let me know if yourun into any issues. Overall, developing on Cygwin for Ruby/Rails isquite nice.

[#156353] Re: MS Access — Sean Armstrong <phinsxiii@...> 2005/09/15

Let me make sure I got this right:

[#156461] Re: MS Access — Sean Armstrong <phinsxiii@...> 2005/09/16

It still refuses to find the lib and include directories even if I use the

[#156506] Re: MS Access — Jacob Quinn Shenker <jqshenker@...> 2005/09/16

Sean,I'm going to try to explain *exactly* what I did, and hopefully you'llsee something you forgot to do.1. Download mysql-essential-4.1.14-win32.msi from mysql.org and install it.2. Download mysql-4.1.13.tar.gz from mysql.org3. Extract the above, and run "./configure -C --without-server" (the-C enables config caching, I use it because the ./configure scriptruns very slowly under Cygwin. Optional, of course)4. Run "make && make install"5. Run "gem install mysql"6. Go make cool rails apps!

[#156444] Hash table questions — EdUarDo <eduardo.yanezNOSPAM@...>

Hi all,

14 messages 2005/09/16

[#156480] Some interesting criticisms of rails — David Balick <davidbalick@...>

may be found in the podcast

24 messages 2005/09/16
[#156530] Re: Some interesting criticisms of rails — "Robert Klemme" <bob.news@...> 2005/09/17

Zed A. Shaw <zedshaw@zedshaw.com> wrote:

[#156624] Language recommendations from ruby persons.... — "Greg Lorriman" <bogus@...>

Dear sirs and madames,

36 messages 2005/09/18

[#156662] Capcha in ruby — Federico <pix@...>

Hello,

23 messages 2005/09/19

[#156708] help with tricky proc/binding issue — "Ara.T.Howard" <Ara.T.Howard@...>

14 messages 2005/09/19

[#156743] The Ruby troll [was: Looking for...] — Gunnar Hjalmarsson <noreply@...>

David H. Adler wrote:

22 messages 2005/09/19

[#156749] ruby idiom for python's for/else while/else — Gergely Kontra <kgergely@...>

Hi!

18 messages 2005/09/19

[#156796] Dissident 0.1, a Ruby dependency injection container — Christian Neukirchen <chneukirchen@...>

Hello,

13 messages 2005/09/20
[#156797] Re: [ANN] Dissident 0.1, a Ruby dependency injection container — "Jason Voegele" <jason@...> 2005/09/20

On Tue, September 20, 2005 8:22 am, Christian Neukirchen said:

[#156801] Re: [ANN] Dissident 0.1, a Ruby dependency injection container — Christian Neukirchen <chneukirchen@...> 2005/09/20

"Jason Voegele" <jason@jvoegele.com> writes:

[#156966] Re: [ANN] Dissident 0.1, a Ruby dependency injection container — Logan Capaldo <logancapaldo@...> 2005/09/21

This is a little OT, but every-time dependency injection comes up I

[#156866] Places for a programmer to live? — Devin Mullins <twifkak@...>

While we seem to be rife with OT threads, I thought I'd throw in an OT

37 messages 2005/09/20

[#156933] Hello, I am a newbie to ruby. — could ildg <could.net@...>

I want learn a script language.

11 messages 2005/09/21

[#157005] Large Ruby Apps ? — "Warren Seltzer" <warrens@...>

I am coming to Ruby having used the usual list of scripting and C* languages. Since Ruby

30 messages 2005/09/21
[#158399] Re: Large Ruby Apps ? — <slonik.az@...> 2005/09/30

Very useful discussion that highlights quite few misconceptions.

[#157007] Re: Large Ruby Apps ? — "Berger, Daniel" <Daniel.Berger@...>

> -----Original Message-----

27 messages 2005/09/21

[#157051] hi, i'm new. plus one question — travis laduke <wrong@...>

I've been forced to work on some php lately and found myself

13 messages 2005/09/22

[#157063] Visual IDEs?? — "Erland" <Erland.Erikson@...>

HI,

24 messages 2005/09/22

[#157080] A question about Intelligent Systems and using Ruby — Daniel Lewis <danieljohnlewis@...>

Yesterday (21/09/2005) I sent an email to Dave Thomas (author of

16 messages 2005/09/22

[#157101] Instantiating a subclass of NilClass. — "Trans" <transfire@...>

I've subclasses NilClass, but don't know how to instantiate it. Any

16 messages 2005/09/22

[#157189] "The class that it is mixed in to..." — John Carter <john.carter@...>

Ok, so I'm documenting a Mixin.

20 messages 2005/09/23
[#157193] Re: "The class that it is mixed in to..." — William Morgan <wmorgan-ruby-talk@...> 2005/09/23

Excerpts from John Carter's mail of 22 Sep 2005 (CDT):

[#157271] Re: "The class that it is mixed in to..." — "David A. Black" <dblack@...> 2005/09/23

Hi --

[#157222] RDE 1.0.0 released — sakazuki <qzs01353@...>

Hi.

16 messages 2005/09/23

[#157299] On accidental unsubscribe messages — "Berger, Daniel" <Daniel.Berger@...>

Hi all,

15 messages 2005/09/23

[#157520] Relative speed of Ruby vs Java for a large compiled app like Freenet — seekingleverage@...

I'm wondering if anyone could shed some light on whether or not it

45 messages 2005/09/25
[#157716] Re: Relative speed of Ruby vs Java for a large compiled app like Freenet — "Isaac Gouy" <igouy@...> 2005/09/26

Martin, perhaps you could collect this stuff and put it into your wiki

[#157540] String#ggsub — Gavin Kistner <gavin@...>

I occasionally find myself with gsub regexp that either eat too much,

21 messages 2005/09/25

[#157565] Rinda frustration — Mark Volkmann <r.mark.volkmann@...>

I'm trying to determine what the methods "move" and "notify" do in the

12 messages 2005/09/26

[#157623] A big thank you to Robby Russell... — Tom Copeland <tom@...>

...for providing another RubyForge mirror via his company, PlanetArgon.

18 messages 2005/09/26
[#157770] Re: A big thank you to Robby Russell... — Gavin Kistner <gavin@...> 2005/09/27

On Sep 26, 2005, at 7:25 AM, Tom Copeland wrote:

[#157826] Re: A big thank you to Robby Russell... — Tom Copeland <tom@...> 2005/09/27

On Tue, 2005-09-27 at 12:43 +0900, Gavin Kistner wrote:

[#157864] Re: A big thank you to Robby Russell... — Sam Mayes <codeslave@...> 2005/09/27

whats the process for becomming a mirror?

[#157871] Re: A big thank you to Robby Russell... — Kirk Haines <khaines@...> 2005/09/27

On Tuesday 27 September 2005 10:24 am, Sam Mayes wrote:

[#157875] Re: A big thank you to Robby Russell... — Tom Copeland <tom@...> 2005/09/27

On Wed, 2005-09-28 at 01:38 +0900, Kirk Haines wrote:

[#157648] Rapid GUI Development with QtRuby — Dave Thomas <dave@...>

I hope y'all don't mind a short announcement, but it seemed relevant.

22 messages 2005/09/26

[#157654] Ruby Threads 101 — Ben <benbelly@...>

I am leading a peer-learning group that is using "Programming Ruby" to

13 messages 2005/09/26

[#157658] Time interval — Daniel Berger <Daniel.Berger@...>

Hi all,

20 messages 2005/09/26

[#157697] Embedded Ruby and Tag Libs — Adam Van Den Hoven <mail@...>

Hey guys,

16 messages 2005/09/26

[#157732] ShortURL 0.7.0 — "Vincent Foley" <vfoley@...>

After a lot of procrastination, I have released ShortURL 0.7.0. I

14 messages 2005/09/26

[#157746] Fwd: Lisp macros — Joe Van Dyk <joevandyk@...>

Whoops, this belongs on ruby-talk... Sorry.

47 messages 2005/09/27
[#157751] Re: Fwd: Lisp macros — James Britt <james_b@...> 2005/09/27

Joe Van Dyk wrote:

[#157779] Re: Fwd: Lisp macros — Jim Freeze <jim@...> 2005/09/27

On 9/26/05, James Britt <james_b@neurogami.com> wrote:

[#157813] Re: Fwd: Lisp macros — Ben <benbelly@...> 2005/09/27

On 9/27/05, Jim Freeze <jim@freeze.org> wrote:

[#157807] How do I (really) encrypt a string in ruby? — Michal Suchanek <hramrach@...>

Hello

10 messages 2005/09/27

[#157854] Class and Iterator Design Question — Jim Freeze <jim@...>

This may be a silly design question, but I always balk at

26 messages 2005/09/27
[#157866] Re: Class and Iterator Design Question — Bob Hutchison <hutch@...> 2005/09/27

[#157889] Re: Class and Iterator Design Question — Jim Freeze <jim@...> 2005/09/27

Wow, thanks for all the responses.

[#157893] Re: Class and Iterator Design Question — "David A. Black" <dblack@...> 2005/09/27

Hi --

[#157896] Re: Class and Iterator Design Question — Jim Freeze <jim@...> 2005/09/27

On 9/27/05, David A. Black <dblack@wobblini.net> wrote:

[#157947] Dynamically generating classes? — Jonas Galvez <jonasgalvez@...>

Hi,

15 messages 2005/09/27

[#158051] Re: creating independent lambdas in loops — "Kroeger Simon (ext)" <simon.kroeger.ext@...>

24 messages 2005/09/28
[#158057] Re: creating independent lambdas in loops — Eric Mahurin <eric_mahurin@...> 2005/09/28

--- "Kroeger Simon (ext)" <simon.kroeger.ext@siemens.com>

[#158074] Re: creating independent lambdas in loops — Gavin Kistner <gavin@...> 2005/09/28

On Sep 28, 2005, at 7:47 AM, Eric Mahurin wrote:

[#158081] Re: creating independent lambdas in loops — Eric Mahurin <eric_mahurin@...> 2005/09/28

--- Gavin Kistner <gavin@refinery.com> wrote:

[#158093] Re: creating independent lambdas in loops — Eric Mahurin <eric_mahurin@...> 2005/09/28

--- Eric Mahurin <eric_mahurin@yahoo.com> wrote:

[#158094] Re: creating independent lambdas in loops — "David A. Black" <dblack@...> 2005/09/28

Hi --

[#158096] Re: creating independent lambdas in loops — Eric Mahurin <eric_mahurin@...> 2005/09/28

--- "David A. Black" <dblack@wobblini.net> wrote:

[#158121] Python to Ruby: Two puzzlements... — "Elf M. Sternberg" <elf@...>

I'm afraid that I'm coming from Python, a B&D language where I'm used to

22 messages 2005/09/28

[#158157] IBM vs. Microsoft vs. ... Ruby? — "itsme213" <itsme213@...>

More "Enterprise Scale" talk over here, with a strong leaning towards

29 messages 2005/09/28
[#158330] Re: IBM vs. Microsoft vs. ... Ruby? — "bonefry" <bellarchitects@...> 2005/09/29

Hi,

[#158258] In your opinion.... — Daniel Lewis <danieljohnlewis@...>

In your opinion(s)....

51 messages 2005/09/29
[#158263] Re: In your opinion.... — Gennady Bystritksy <gfb@...> 2005/09/29

Daniel Lewis wrote:

[#158265] Re: In your opinion.... — Daniel Lewis <danieljohnlewis@...> 2005/09/29

> Too lazy to do your own research? It happens ;-). For a starter, check

[#158311] rush 0.1.bandicoot: object-oriented shell goodness (rationed for your health)! — The rush folks <rush-ruby-ml@...>

= rush-0.1.bandicoot

10 messages 2005/09/29

[#158327] Operator Overloading << — "matt.hulse@..." <matt.hulse@...>

Is there a way to overload '<<' in the Array class?

19 messages 2005/09/29

[#158460] Ruby licence... — netspam@...

I understand that the distribution of Ruby is under the GPL.

25 messages 2005/09/30
[#158600] Re: Ruby licence... — "Gregory Brown" <gregory.t.brown@...> 2005/10/02

The Ruby License and the License of Ruby are two different things.

[#158620] Re: Ruby licence... — Kevin Brown <blargity@...> 2005/10/02

On Saturday 01 October 2005 20:51, Gregory Brown wrote:

[#158659] Re: Ruby licence... — Christian Neukirchen <chneukirchen@...> 2005/10/02

Kevin Brown <blargity@gmail.com> writes:

[#158663] Re: Ruby licence... — Kevin Brown <blargity@...> 2005/10/02

On Sunday 02 October 2005 10:56, Christian Neukirchen wrote:

[#158690] Re: Ruby licence... — Christian Neukirchen <chneukirchen@...> 2005/10/02

Kevin Brown <blargity@gmail.com> writes:

[#158692] Re: Ruby licence... — Kevin Brown <blargity@...> 2005/10/02

On Sunday 02 October 2005 12:45, Christian Neukirchen wrote:

[#158497] Interest in Boost::Ruby — Alan Gutierrez <alan-ruby-talk@...>

I'd like to build a CSS renderer in modern C++ as an enthusist's

24 messages 2005/09/30

[SUMMARY] NDiff (#46)

From: Ruby Quiz <james@...>
Date: 2005-09-15 12:49:54 UTC
List: ruby-talk #156232
Both solutions had some really interesting material in them.  I would certainly
talk about both, if time and space allowed.

Paul Vaillant had some interesting parsing code (see DataFile.parse_line()) and
comparison code (see DataFile::CompareResults.compare()).  Paul's entire
solution was also very clean and readable, though it did come out a bit longer
than Daniel Sheppard's code.  Finally, Paul's code is over three times faster,
which could be a real asset for significant data sets.

Daniel's code is the one I want to look at below, because of the way it handles
an interesting Ruby problem.  What makes this challenge fun, I think, is that
it's one of the edge cases where Ruby's internal iterator can feel awkward. 
You're always walking through two separate collections in this problem.  Ruby
has some nice solutions for this, buried in the dark corners of its standard
library, but many of us just aren't aware of them.  One of these tools,
SyncEnumerator from the generator library, is heavily used in the following
code.  Let's see how something like that can make a real difference in the end
result:

	require 'generator'
	require 'pathname'
	require 'optparse'
	require 'bigdecimal'
	
	class NumberLine
		include Enumerable
		def initialize(line)
			@line = line
		end
		def each
			@line.scan( / ((-)?([0-9]+|\.)
			              \.?([0-9]+)?[Ee]?
			              ([-+]?[0-9]+)?) /x) do |match|
				yield BigDecimal.new(match[0])
			end	
		end
		def to_s
			@line
		end
	end
	
	# ...

This is a simple encapsulation of a single line of one or more numbers.  The
only method of interest here is each(), which scan()s the line looking for all
the numbers it can find.  That lengthy Regexp just matches an optional minus
sign, followed by some digits (or a period), optionally followed by a period and
some more digits, optionally following by an E or e and another number.  This
isn't a fool-proof match since it will catch a String like "-." or even "..",
but it's probably good enough for most cases.  Each number matched is fed to
BigDecimal and then yielded to a given block.  The use of the library here slows
things down a bit, but it avoids floating point inaccuracies too, which is more
important to this challenge.

	# ...
	
	class NumericalDifferencer
		attr_accessor :digits, :tolerance
		def initialize
			@digits = 0
			@tolerance = 0.0
		end
		def each_diff(file1, file2)
			line = 0
			diff = nil
			SyncEnumerator.new(file1, file2).each do |line1, line2|
				line1, line2 = NumberLine.new(line1), NumberLine.new(line2)
				line += 1
				num_enum =  SyncEnumerator.new(line1, line2)
				if num_enum.all? do |a,b|
					unless @digits == 0
						a,b = a.round(@digits-1), b.round(@digits-1)
					end
					(a - b).abs <= @tolerance 
				end
					if diff
						yield diff
						diff = nil
					end
				else
					diff = NumericalDiff.new(line) unless diff
					diff.add_lines(line1, line2)
				end
			end
			yield diff if diff
		end
	end
	
	# ...

Here we get into the actual file comparison code and some SyncEnumerator fun. 
The first SyncEnumerator created here walks through the two files given in step.
Each iteration of the block receives the next line from both files.  Those lines
are turned into NumberLine objects, which we have already seen.  Then a
SyncEnumerator is made from those objects, which allows the code to traverse
each number found in both lines, again in step.  That object is used in the if
condition to ensure that all?() numbers in the line are within the needed
tolerance (rounding if requested).  When any numbers of the lines don't match
close enough a NumericalDiff object is created and the current lines, plus any
following lines that also differ, are added to it.  When the NumericalDiff is
complete, because the code has returned to matching lines or completed running
through the files, the diff object is yielded to the provided block.

Let's take a look at that NumercialDiff class:

	# ...
	
	class NumericalDiff
		attr_reader :start_line, :left, :right
		def initialize(start_line)
			@start_line = start_line
			@left = []
			@right = []
		end
		def add_lines(line1, line2)
			@left << line1
			@right << line2
		end
		def to_s
			lines = "#{@start_line},#{@start_line + @left.length - 1}"
			str = "#{lines}c#{lines}\n"
			str << @left.collect { |x| "< #{x}" }.join
			str << "---\n"
			str << @right.collect { |x| "> #{x}" }.join
		end
	end
	
	# ...

No black magic in here.  The work method is to_s() and it should be easy enough
to see that it's just creating the quiz format there.

That's really the majority of the solution.  The rest is mainly option parsing:

	# ...
	
	differ = NumericalDifferencer.new
	quiet = false
	statistics = false
	
	opts = OptionParser.new do |opts|
	        opts.banner = "Usage: #{$0} [options] file1 file2"
			
	        opts.separator ""
	        opts.separator "Numerically compare files line by line, " +
	                       "numerical field by numerical field."
	        opts.separator ""
	        opts.on("-d", "--digits INT", Integer,
	                "Maximum number of significant digits that should match.",
	                "(default: 0)") do |digits|
	          differ.digits = digits
	        end
	        opts.on("-t", "--tolerance DBL", String, 
	                "Tolerate <= DBL distance between numbers.",
	                "(default: 0.0)") do |tolerance|
	          differ.tolerance = BigDecimal.new(tolerance)
	        end	
	        opts.on("-h", "--help", "Output this help.") do |help|
			puts opts
			exit 0
	        end
		opts.on("-q", "--quiet", "No output, just exit code.") do |value|
			quiet = value
		end
		opts.on("-s", "--statistics",
		        "Provide comparison statistics only.") do |value|
			statistics = value
		end	
	end
	
	# ...

The top few lines there create a variables to hold the diff tools and setting
information.  Then the last chunk of code is OptionParser 101.

Finally, here's the code that kicks it all off:

	# ...
	
	begin
		opts.parse!(ARGV)
		if quiet && statistics
			raise "--quiet and --statistics are mutually exclusive"
		end
		raise "Must pass two filenames" unless ARGV.length == 2
		files = ARGV.collect { |x| Pathname.new(x) }
		files.each do |f| 
			unless f.exist? && f.file?
				raise "'#{f}' does not exist"
			end
		end
		File.open(files[0]) do |file1|
			File.open(files[1]) do |file2|
				if(statistics)
					distances = []
					SyncEnumerator.new(file1, file2).each do |line1, line2|
						line1, line2 = NumberLine.new(line1),
						               NumberLine.new(line2)
						SyncEnumerator.new(line1, line2).each do |num1, num2|
							distances << (num1 - num2).abs
						end
					end
					class << distances
						def median
							sorted = self.sort
							mid = sorted.size / 2
							if sorted.size % 2 == 0
							    (sorted[mid] + sorted[mid - 1]) / 2
							else
							    sorted[mid]
							end
						end
						def mean
							self.inject(0) { |x, sum| sum + x / self.size}
						end
					end
					puts(<<-EOF)
	Numbers compared: #{distances.size}
	Distance range: #{distances.min}..#{distances.max}
	Median distance: #{distances.median}			
	Mean distance: #{distances.mean}
					EOF
				elsif(quiet)
					differ.each_diff(file1, file2) do |diff|
						exit 1
					end
					exit 0
				else
					different = false
					differ.each_diff(file1, file2) do |diff|
						different = true
						puts diff
					end
					exit(different ? 1 : 0)
				end
			end
		end	
	rescue => e
		warn e
		warn opts
		exit 1
	end

I know that looks like a lot of code, but the majority of it is the extra credit
part of the challenge.  If you can spot that big if statement in the middle,
you'll see that the majority of the code is in the first branch.  That part
calculates statistics, by implementing its own inline custom traversal of the
files (again with SyncEnumerator).  The really interesting feature in this code
is that the results are just compiled into an Array and then that Array is
modified with extra methods to make outputting the results easy.  If you're not
familiar with Ruby's class << some_object ... end idiom, it simply adds the
methods to just that one object.  A handy trick put to good use here, I think.

The other two very short branches (elsif and else), actually solve the quiz. 
They just react according to the each_diff() method we examined earlier.

It's probably worth mentioning again here, the generator library is pure Ruby
and makes use of continuations, which can be quite slow.  BigDecimal is never
going to be as fast as using Floats either, for obvious reasons.  The result is
that this code is quite a bit slower than Paul's solution.  (Over three times
slower, in my tests.)  That doesn't affect small data sets, like the ones in the
quiz, very much, but you may start waiting a bit on longer inputs.

My thanks to both quiz solvers, for showing off some super cool Ruby techniques.

Tomorrows quiz is a simple challenge for all you web application junkies, that
may just prove interesting to the community at large.  Join in the fun and show
us just how cool your favorite web application framework can be...

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