Ruby Weekly News 6th - 12th February 2006


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http://www.rubyweeklynews.org/20060212.html

Ruby Weekly News 6th - 12th February 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
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by Tim S…

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User Group News

 * OK.rb's First Meeting
 -----------------------

   James Edward G. II announced the first meeting of the Oklahoma 

Ruby
Users Group: March 14th 2006 at the University of Central
Oklahoma.

   | This first meeting is being organized by myself and Grant 

Schofield
| and we will be providing some educational content to get us
going. I
| will give a “Uniquely Ruby” talk, focusing on those things that
make
| Ruby stand out from other languages. Grant is giving a
first-look at
| Rails presentation as well. Both talks will be aimed at Ruby
| programmers of all skill levels.

 * Boulder-Denver Ruby Group - February 15th
 -------------------------------------------

   Marty H. said that the Boulder-Denver Ruby Group are holding 

their
February meeting on Wednesday 15th.

   "David A. Black will be joining our group that night and will be
   presenting for our group."

 * February Ruby events in the SF Bay Area
 -----------------------------------------

   Rich M. posted a list of Ruby events in the San Francisco Bay 

Area
during February.

   The SF Ruby Meetup is on the 21st, and the Beer & Scripting SIG 

is on
the 22nd.

Quote of the Week

 * Ruby's lisp features.
 -----------------------

Let’s call it MatzLisp from now on. :wink:

                                                    matz.

Threads

FasterGenerator (#66)

James Edward G. II came up with this week’s Ruby Q…

    end

Ruby’s standard Generator class was recently re-written to improve
performance. Your mission is to make it even faster.

Matz: “I’d be happy to replace current implementation of generator.rb
with
the winning one.”

Some very promising benchmarks were posted.

Getting last character from a string

draco draco asked for a nice way of getting the last character in a
String.

Several people said that you can use negative indices to count
backwards
from the end of String and Array objects, for example -1 for the end,
-2
for the second-to-last etc.

Based off a post by Gennady B.,

s = “abc”
s[-1] # 99
s[-1].chr # “c”

Adding properties to a method?

jonT wanted to know how to add `properties’ to Method objects.

class Method
attr_accessor :foo
end

def bar
“some_res”
end

method(:bar).foo = 1

puts(method(:bar).foo) # => nil instead of 1

The problem is that method(:bar) returns a new Method instance each
time
it is called.

As is often the case, the Facets project has a solution. It includes
method!, which returns the same Method instance each time it’s given
the
same method name.

(Not so good if some code redefines the method in between two calls
to
method! though.)

Ruby port for Nokia 770 Wireless Internet Tablet

Ken Hilton successfully ported Ruby 1.8.4 to the “Nokia 770 Wireless
Internet Tablet” (which runs Linux).

“Before porting Ruby to it, it was love at first sight. Now I’m
ecstatic.”

He will be posting a tarball once he’s setup a rubyforge account.

how to do instance_eval with arguments

Jim W.: “I’m prototyping a DSL and came across a situtation
where I
have a lambda that I would like to give to instance_eval, but the
lambda
takes arguments. Instance_eval will not supply any arguments when
evaluating the lambda and I don’t see a straightforward way around
this.”

Matz said that Ruby in CVS HEAD has instance_exec for this.

See also [Frost-safe DSL’ing with instance_exec] by Mauricio
Fernandez,
which gives a safe implementation of instance_exec for Ruby 1.8.

The above article was found via Christian N.'s [Anarchaia].
Chris also questioned why a new method was added, rather than just
making
instance_eval pass any arguments it receives.

For those readers who are confused about why you would ever need this
feature (as was I initially), note that it is never needed in the
usual
case when the block passed in is defined on the spot.

Not useful

value = 42
obj.instance_exec(value) { |v| some_method(v) }

Lexical scoping means we could just write

value = 42
obj.instance_eval { some_method(value) }

Consider the case, though, where a block taking arguments has been
defined
somewhere else, and we now want to instance_eval it.

This doesn’t achieve anything. blk isn’t evaluated against obj.

value = 42
obj.instance_eval { blk.call(value) }

This works

value = 42
obj.instance_exec(value, &blk)

New Releases

A few of the highlights this week …

Watir WebRecorder for Ruby

Marcus Tettmar announced Watir WebRecorder, "a version of WebRecorder
that
creates Ruby/Watir code. Watir WebRecorder is a multi-tabbed web
browser
that records web activity in Internet Explorer and creates Ruby code
which
uses the Watir library for IE automation.

WebRecorder is designed to speed up the creation of web testing and
web
automation scripts."

Nitro + Og 0.28.0: Cacheable, Ruby Query Language, Mongrel, Og cloning

George M. released new versions of Nitro and Og, a web
application framework and object-relational mapper respectively.

Caching and querying were improved, bugs fixed, plus a bunch of other
new
features.

Spreadsheet::ParseExcel

Hannes W. announced a pure-Ruby library for reading Excel files. It
is
based off the Perl module of the same name.