# 26th December 2005 - 1st January 2006

**URL:** <https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101>\
**Category:** Ruby\
**Created:** [January 3, 2006, 10:30am UTC](https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101 "2006-01-03T10:30:37Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [January 3, 2006, 10:30am UTC](https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101/1 "2006-01-03T10:30:37Z")

</div>

[http://www.rubyweeklynews.org/20060101.html](http://www.rubyweeklynews.org/20060101.html)

# Ruby Weekly News 26th December 2005 - 1st January 2006

Ruby Weekly News is a summary of the week’s activity on the  
ruby-talk mailing list / the comp.lang.ruby newsgroup / Ruby forum,  
brought to you by Tim S…

A short one this week!

[Contribute to the next newsletter]

# Articles and Announcements

```
 * ICFP Contest Dates Are Set
 ----------------------------

   James Edward G. II said that the International Conference of
   Functional Programming have announced the dates for 2006's 

```

programming  
contest.

```
   "Ruby participation has been pretty small in the past, so it 

```

would be  
great to see some solid Ruby entries this year. Ruby Q. will  
take a  
break for the contest, to encourage others to enter and give me  
time  
to make my own entry."

```
 * RRobots Tournament Results
 ----------------------------

   Ruby Q. #59 set out the challenge of writing bots to play in an
   RRobots Tournament, held just after Christmas.

   The results are now out, with Jannis Harder's bot Ente besting 10
   other entries to win the tournament.

   Jannis also wins a real robot: the Desktop R/C Mini-Rover from
   ThinkGeek.com. (Thanks to Simon Kröger and James Edward G. II.)

 * Forthcoming 2nd ed. of _The Ruby Way_
 ---------------------------------------

   This thread began a couple of weeks ago, but we missed it 

```

previously.

```
   Hal F. announced the second edition of his book `The Ruby 

```

Way’;  
“ink is dry on the contract” and it’s aimed to be ready for the  
second  
quarter of 2006.

```
   There was much discussion about the current edition, what 

```

libraries  
should be covered in the second edition, and also in response to  
a  
question by Patrick H., “what would your idea table of  
contents  
look like in an Advanced Ruby book?”

```
   David A. Black's upcoming book "Ruby for Rails: Ruby techniques 

```

for  
Rails developers" was also noted. It is due April 2006.

# Threads

## ActiveRecord

Diego: “I was wondering if ActiveRecord support was available for  
database  
access without requiring Ruby on Rails?”

The answer is yes, “Active Record works very well on standard alone  
scripts” (David Heinemeier H.).

As an alternative, George M. mentioned his Og library, which  
fills the same role as ActiveRecord.

## scoped\_require 0.0

“… and from the substratum, it arises …”

Devin M.: “scoped\_require provides an optional parameter to  
Kernel#require to allow you to shove the created modules/classes into  
some  
sandboxy container module. I use it to prevent namespace collision  
with an  
external library. It’s a hack. Heed the version number.”

It works by reading the .rb file being required, and evaling the  
result.

Eero S. vaguely recalled someone posting an alternative  
implementation of this concept - probably thinking of Wrapped Modules  
by  
Austin Z. in May 2005.

The example given in that post:

module My; end  
module Your; end  
require\_wrap ‘cgi’, My  
require\_wrap ‘cgi’, Your

puts My::CGI.escape(“hello, world”)  
puts Your::CGI.escape(“hello, world”)

Austin’s implementation works by first calling Module.constants to  
find  
out all the top-level constants, then calling require, followed by  
Module.constants again to find which constants have been added. It  
then  
`moves’ those constants under the desired namespace.

Both implementations cause problems in some cases. The most  
significant  
(and intractible) one seems to be the situation when the require’d  
file  
includes code like the following:

# foo.rb

class String  
def hello  
“hello #{self}”  
end  
end

require ‘foo’, :module =\> F

Should the hello method be added to Ruby’s standard String class, or  
should a new class F::String be created? (Would your answer be  
different  
if the class was called Util, and had just happened to be defined by  
another library?)

Austin’s solution does the former, while Devin’s does the latter.

Arguably, the `correct’ solution is to create F::String, and say that  
foo.rb should have written class ::String if it really wanted to add  
the  
method to the standard String class.

This will be no consolation to all the libraries that don’t use the  
::  
prefix. For example, set.rb in the core Ruby library says module  
Enumerable, not module ::Enumerable.

## Using Float For Currency

Hunter’s Lists was using Floats to represent monetary values, but  
wanted  
to print e.g. “9.76” instead of “9.756”.

The immediate answer to the question is to use sprintf (or printf)  
for  
rounding:

amount = 9.756  
rounded = sprintf(“%.2f”, amount) # == “9.76”

Several people pointed out though that you shouldn’t use Floats to  
represent currency.

Mental: “There are a lot of really nasty subtle issues that will lose  
money between the cracks.”

This applies to any programming language, not just Ruby. An example  
given  
by Malte M.: 0.2 - 0.05 - 0.15 will be approximately  
2.77555756156289e-17, not zero.

Stephen W.: “Floating point numbers represent an extremely wide  
range  
of values - much wider than their integer counterparts. This is  
handled  
through an exponent and mantissa. For this ability, they trade off  
precision.”

The Ruby solution for exact decimals is BigDecimal:

require ‘bigdecimal’

a = BigDecimal.new(“0.2”)  
b = BigDecimal.new(“0.05”)

c = a / b

Operations with BigDecimal are always exact (but slower than with  
Float),  
and so it is safe to use with currencies and other situations where  
any  
loss of precision is unacceptable.

## Idiom wanted: do-while

Adam S. asked how to write a “do-while” loop in Ruby, in order to  
remove the repetition in the below code:

b = simulate(b,m)  
while another\_turn?(b,m)  
b = simulate(b,m)  
end

James Edward G. II suggested loop, break unless, as in

loop do  
b = simulate(b,m)  
break unless another\_turn?(b,m)  
end

Ruby does support the following, which is just like a “do-while” loop  
in  
other languages, however Matz recently said on the ruby-core mailing  
list  
“Don’t use it please. I’m regretting this feature, and I’d like to  
remove  
it in the future if it’s possible.”

begin  
b = simulate(b,m)  
end while another\_turn?(b,m)

## Ruby on the mobile

“Do anyone knows if there is a Ruby version for cellphones and other  
mobile devices on the make?”-Marcelo Paniagua.

Treefrog asked someone in the Mobile Devices division of Motorola  
about  
this a while ago, but was told that only Java and BREW were currently  
supported.

Gene T. noted that Python is making progress in this area, linking  
to a  
Python for Mobile Devices page, which lists a number of ports  
including  
official Nokia support and downloads for “Series 60” phones. (The  
first  
release by Nokia was over a year ago.)

People have previously reported success in running Ruby on the Sharp  
Zaurus PDA (which runs Linux) and on Windows CE.

## Ncurses - how do you get mousemask working?

Richard L. couldn’t get the mousemask to work in the Ncurses  
library.

| A few other projects have the line with `Ncurses::mousemask…’ in  
them  
| - but it’s always commented out… like they couldn’t get it  
working  
| either.

Paul D. replied “They couldn’t”, and posted a one-liner patch to  
Ruby’s ncurses library to fix a bug.

Hopefully the authors of the other projects find out about this.

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [January 3, 2006, 10:30am UTC](https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101/2 "2006-01-03T10:30:40Z")

</div>

[Now with correct thread name. Was missing the "Ruby Weekly News "  
prefix.]

[http://www.rubyweeklynews.org/20060101.html](http://www.rubyweeklynews.org/20060101.html)

# Ruby Weekly News 26th December 2005 - 1st January 2006

Ruby Weekly News is a summary of the week’s activity on the  
ruby-talk mailing list / the comp.lang.ruby newsgroup / Ruby forum,  
brought to you by Tim S…

A short one this week!

[Contribute to the next newsletter]

# Articles and Announcements

```
 * ICFP Contest Dates Are Set
 ----------------------------

   James Edward G. II said that the International Conference of
   Functional Programming have announced the dates for 2006's 

```

programming  
contest.

```
   "Ruby participation has been pretty small in the past, so it 

```

would be  
great to see some solid Ruby entries this year. Ruby Q. will  
take a  
break for the contest, to encourage others to enter and give me  
time  
to make my own entry."

```
 * RRobots Tournament Results
 ----------------------------

   Ruby Q. #59 set out the challenge of writing bots to play in an
   RRobots Tournament, held just after Christmas.

   The results are now out, with Jannis Harder's bot Ente besting 10
   other entries to win the tournament.

   Jannis also wins a real robot: the Desktop R/C Mini-Rover from
   ThinkGeek.com. (Thanks to Simon Kröger and James Edward G. II.)

 * Forthcoming 2nd ed. of _The Ruby Way_
 ---------------------------------------

   This thread began a couple of weeks ago, but we missed it 

```

previously.

```
   Hal F. announced the second edition of his book `The Ruby 

```

Way’;  
“ink is dry on the contract” and it’s aimed to be ready for the  
second  
quarter of 2006.

```
   There was much discussion about the current edition, what 

```

libraries  
should be covered in the second edition, and also in response to  
a  
question by Patrick H., “what would your idea table of  
contents  
look like in an Advanced Ruby book?”

```
   David A. Black's upcoming book "Ruby for Rails: Ruby techniques 

```

for  
Rails developers" was also noted. It is due April 2006.

# Threads

## ActiveRecord

Diego: “I was wondering if ActiveRecord support was available for  
database  
access without requiring Ruby on Rails?”

The answer is yes, “Active Record works very well on standard alone  
scripts” (David Heinemeier H.).

As an alternative, George M. mentioned his Og library, which  
fills the same role as ActiveRecord.

## scoped\_require 0.0

“… and from the substratum, it arises …”

Devin M.: “scoped\_require provides an optional parameter to  
Kernel#require to allow you to shove the created modules/classes into  
some  
sandboxy container module. I use it to prevent namespace collision  
with an  
external library. It’s a hack. Heed the version number.”

It works by reading the .rb file being required, and evaling the  
result.

Eero S. vaguely recalled someone posting an alternative  
implementation of this concept - probably thinking of Wrapped Modules  
by  
Austin Z. in May 2005.

The example given in that post:

module My; end  
module Your; end  
require\_wrap ‘cgi’, My  
require\_wrap ‘cgi’, Your

puts My::CGI.escape(“hello, world”)  
puts Your::CGI.escape(“hello, world”)

Austin’s implementation works by first calling Module.constants to  
find  
out all the top-level constants, then calling require, followed by  
Module.constants again to find which constants have been added. It  
then  
`moves’ those constants under the desired namespace.

Both implementations cause problems in some cases. The most  
significant  
(and intractible) one seems to be the situation when the require’d  
file  
includes code like the following:

# foo.rb

class String  
def hello  
“hello #{self}”  
end  
end

require ‘foo’, :module =\> F

Should the hello method be added to Ruby’s standard String class, or  
should a new class F::String be created? (Would your answer be  
different  
if the class was called Util, and had just happened to be defined by  
another library?)

Austin’s solution does the former, while Devin’s does the latter.

Arguably, the `correct’ solution is to create F::String, and say that  
foo.rb should have written class ::String if it really wanted to add  
the  
method to the standard String class.

This will be no consolation to all the libraries that don’t use the  
::  
prefix. For example, set.rb in the core Ruby library says module  
Enumerable, not module ::Enumerable.

## Using Float For Currency

Hunter’s Lists was using Floats to represent monetary values, but  
wanted  
to print e.g. “9.76” instead of “9.756”.

The immediate answer to the question is to use sprintf (or printf)  
for  
rounding:

amount = 9.756  
rounded = sprintf(“%.2f”, amount) # == “9.76”

Several people pointed out though that you shouldn’t use Floats to  
represent currency.

Mental: “There are a lot of really nasty subtle issues that will lose  
money between the cracks.”

This applies to any programming language, not just Ruby. An example  
given  
by Malte M.: 0.2 - 0.05 - 0.15 will be approximately  
2.77555756156289e-17, not zero.

Stephen W.: “Floating point numbers represent an extremely wide  
range  
of values - much wider than their integer counterparts. This is  
handled  
through an exponent and mantissa. For this ability, they trade off  
precision.”

The Ruby solution for exact decimals is BigDecimal:

require ‘bigdecimal’

a = BigDecimal.new(“0.2”)  
b = BigDecimal.new(“0.05”)

c = a / b

Operations with BigDecimal are always exact (but slower than with  
Float),  
and so it is safe to use with currencies and other situations where  
any  
loss of precision is unacceptable.

## Idiom wanted: do-while

Adam S. asked how to write a “do-while” loop in Ruby, in order to  
remove the repetition in the below code:

b = simulate(b,m)  
while another\_turn?(b,m)  
b = simulate(b,m)  
end

James Edward G. II suggested loop, break unless, as in

loop do  
b = simulate(b,m)  
break unless another\_turn?(b,m)  
end

Ruby does support the following, which is just like a “do-while” loop  
in  
other languages, however Matz recently said on the ruby-core mailing  
list  
“Don’t use it please. I’m regretting this feature, and I’d like to  
remove  
it in the future if it’s possible.”

begin  
b = simulate(b,m)  
end while another\_turn?(b,m)

## Ruby on the mobile

“Do anyone knows if there is a Ruby version for cellphones and other  
mobile devices on the make?”-Marcelo Paniagua.

Treefrog asked someone in the Mobile Devices division of Motorola  
about  
this a while ago, but was told that only Java and BREW were currently  
supported.

Gene T. noted that Python is making progress in this area, linking  
to a  
Python for Mobile Devices page, which lists a number of ports  
including  
official Nokia support and downloads for “Series 60” phones. (The  
first  
release by Nokia was over a year ago.)

People have previously reported success in running Ruby on the Sharp  
Zaurus PDA (which runs Linux) and on Windows CE.

## Ncurses - how do you get mousemask working?

Richard L. couldn’t get the mousemask to work in the Ncurses  
library.

| A few other projects have the line with `Ncurses::mousemask…’ in  
them  
| - but it’s always commented out… like they couldn’t get it  
working  
| either.

Paul D. replied “They couldn’t”, and posted a one-liner patch to  
Ruby’s ncurses library to fix a bug.

Hopefully the authors of the other projects find out about this.

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [January 3, 2006, 2:40pm UTC](https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101/3 "2006-01-03T14:40:08Z")

</div>

On Jan 3, 2006, at 3:27 AM, Tim S. wrote:

> [http://www.rubyweeklynews.org/20060101.html](http://www.rubyweeklynews.org/20060101.html)
> 
> # Ruby Weekly News 26th December 2005 - 1st January 2006

[snip]

> ```
> great to see some solid Ruby entries this year. Ruby Q.  
> 
> ```
> 
> will take a  
> break for the contest, to encourage others to enter and give  
> me time  
> to make my own entry."

Uh, Tim… I said that in February of 2005 about last year’s  
contest… 😉

[http://rubyurl.com/EhL](http://rubyurl.com/EhL)

James Edward G. II

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [January 3, 2006, 8:30pm UTC](https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101/4 "2006-01-03T20:30:27Z")

</div>

James Edward G. II wrote:

> On Jan 3, 2006, at 3:27 AM, Tim S. wrote:
> 
> > [http://www.rubyweeklynews.org/20060101.html](http://www.rubyweeklynews.org/20060101.html)  
> > […]  
> > James Edward G. II said that the International Conference of  
> > Functional Programming have announced the dates for 2006’s  
> > programming contest.  
> > […]  
> > Uh, Tim… I said that in February of 2005 about last year’s  
> > contest… 😉

Oh dear.

Also, the “Active Record” and “Ruby on the mobile” threads were both  
from July 2005.

My google-groups-screen-scraping-script-breaketh.

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [January 3, 2006, 8:50pm UTC](https://www.ruby-forum.com/t/26th-december-2005-1st-january-2006/56101/5 "2006-01-03T20:50:48Z")

</div>

On 1/3/06, removed\_email\_address@domain.invalid [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Oh dear.
> 
> Also, the “Active Record” and “Ruby on the mobile” threads were both  
> from July 2005.

No wonder I was so confused, because I read ruby-talk over the  
holidays and didn’t remember much of that!

> My google-groups-screen-scraping-script-breaketh.

Y2K6 bug? 😉

Ryan