ruby-talk

Hi folks!

How are you?  In Japan, June is also known as the rainy season which
called ``Tsuyu''. In this month, it is not only hot but also wet.
Every food go bad in no time. Everyday they bring umbrella. It is very
gloomy... sigh.

Few days ago, I found very nice word in Hikaru UTADA's site:

	``The nice thing about rain'', said Eeyore, ``is that it
	always stops. Eventually''.

Yeah! It is the truth.  Eeyore is a great philosopher, I think. 

# Hikaru UTADA is the best selling singer in Japan. 
# Eeyore is the famous mule as one of Winnie the Pooh's friends. 

Today, I pick up 10 topics -- 4 contrib, 4 reports and 2 Q&A. 
Here we go!
    ______________________________________________________________________

	Contibutions
	------------

	[ruby-list:14900] Rubyfaq-990608

	Endo-san put rubyfaq-990608.tar.gz. 
	It's available via http://www.netlab.co.jp/ruby/FAQ/rubyfaq.html
    ______________________________________________________________________

	[ruby-list:14761] CGI.rb

	Aoyama-san put CGI.rb version 0.20.  The main change is multipart
	form support:
	
require "CGI"
query = CGI.new
html = CGI.new("html3")
CGI::print{
  html.multipart_form{
    html.file_field("field_name") +
    html.submit
  } +
  if query.include?("field_name")
    html.pre{
      "original_filename --> " +
        query["field_name"][0].original_filename + "\n" +
      "local_path --> " +
        query["field_name"][0].local_path + "\n" +
      "local_file_size --> " +
        query["field_name"][0].stat.size.to_s + "\n" +
      "content_type --> " +
        query["field_name"][0].content_type + "\n" +
      query["field_name"][0].read
    }
  else
    ""
  end
}
    ______________________________________________________________________

	[ruby-list:14804] telnet.rb(0.20)
	
	Aoyama-san put telnet.rb version 0.20. 
	It is included now in the next release of ruby. 
    ______________________________________________________________________

	[ruby-list:14994] FreeBSD port kit for Ruby/Gtk

	Fukuma-san release port kit of Ruby/Gtk for FreeBSD at his site:

ftp://ftp8.big.or.jp/pub/usr8/yasuf/ports/ruby-gtk-0.18.19990611.tar.gz

	He also submitted some port kits to http://www.freebsd.org/

	ruby-postgres-0.4.1
	ruby-readline-1.7.1
	irb-0.5.1
    ______________________________________________________________________

	Reports
	-------

	[ruby-list:14660] Ruby on Be

	I tried to compile ruby-1.2.5 on BeOS(Intel.R4). Successfully done it
	expect one warning in math.c.  But `make test' failed (Segmentation
	fault in line 922); nevertheless I'm using with fighting spirit!
	It works well till now. 
    ______________________________________________________________________

	[ruby-list:14667] [BUG] def foo; foo end; foo

	The following raise [BUG] Segmentation fault:
def foo; foo end; foo

	on ruby 1.2.5(99/04/13) [i386-djgpp]. 


	[ruby-list:14687] Re: [BUG] def foo; foo end; foo
	
	> Aha! STACK_LEVEL_MAX may be larger if checking frequency is set
	> higher. 

	For the present, please use 0x180000 instead of 0x100000 in main.c. 
    ______________________________________________________________________

	[ruby-list:14739] manual bug

	In ruby-man-1.x/String.html:

        ljust(width)
        rjust(width)
        center(width)
        -       Returns right filled, left filled, centered string,
        +       Returns left filled, right filled, centered string,
               respectively. If the string is longer than width, returns
               the string itself without modification.
    ______________________________________________________________________

	Q and A
	-------

	[ruby-list:14642] Re: archive.rb

	Question:
		I'm writing archive.rb which manages archive files. 
		To define methods for each file type, I try mix-in
		for an object. But it doesn't work, fail at `include @type'. 
		Why?

#!/usr/bin/ruby
include FileTest

class Archive
  def what_type
    raise "file #{@file} not found" unless exist?(@file)
    @file[-3,3].downcase == 'lzh' and return Lha
    @file[-3,3].downcase == 'tgz' and return Tar
    @file[-6,6].downcase == 'tar.gz' and return Tar
    `file #{@file}` =~  /lha.+archive/i  and return Lha
    raise "file #{@file} is not an archive file."
  end
  def initialize (file)
    @file=file
    @type=what_type
    include @type
  end
  def print_id
    puts "#{name}"
    puts "This file is '#{@file}'."
  end
  def delete_extracted_files
    @extracted_files.each { |f| File.unlink(f) if exist?(f) }
  end
end

module Lha
  def list (file)
    `lha l #{file}`.split (/\n/)[2..-3].filter { |l| l[46..-1]}
  end
  def extract (file)
    @extracted_files=`lha xf #{file}`.split (/\n/).filter { |l| l.split[0] }
  end
end

module Tar
  def list (file)
    `tar tzf #{file}`.split (/\n/)
  end
  def extract (file)
    @extracted_files=`tar xzvf #{file}`.split (/\n/)
  end
end


	Answer:
		`include' is for a module/class. Use `extend' to append 
		features to an object.  In this case, just `extend @type'.
		The corrected version of this module will be put on the
		sample. 
    ______________________________________________________________________

	[ruby-list:14746] gsub("'", "\\'")
	
	Question:
		What can replace ' by \' ?
		I don't understand the result as follows:

% cat gsub.rb
s="'Test"
p s.gsub("'", "\'")
p s.gsub("'", "\\'")
p s.gsub("'", "\\\'")
p s.gsub("'", "\\\\'")
p s.gsub("'", "\\\\\'")
p s.gsub("'", "\\\\\\'")
p s.gsub("'", "\\")

% ruby gsub.rb
"'Test"
"TestTest"
"TestTest"
"\\'Test"
"\\'Test"
"\\TestTest"
"\\Test"

	Answer:
		I often fall into backslash trap too. 
		For a quoted string (''), backslash escaped quote (\') and 
		backslash escaped backslash (\\) would be interpred,
		for a double quote string (""),  newline (\n) and various
		escape sequences.  *After* those interpretations gsub
		seeks \1 or \&. So, a backslash seems disappeared. 
		The following illustrates such situation. 

gsub("'", "\\'")
gsub  '    \'           <- interpretation by ruby's lexical analyzer
gsub  '    Test         <- interpretation by gsub


gsub("'", "\\\'")
gsub  '    \'           <- interpretation by ruby's lexical analyzer
gsub  '    Test         <- interpretation by gsub
		

gsub("'", "\\\\'")
gsub  '    \\'          <- interpretation by ruby's lexical analyzer
gsub  '    \'           <- interpretation by gsub

		The last one is what you want.  All you mistake is 
		not realize the method `p' prints \ as \\. 

		Maybe, the following doesn't bother with such problem

p s.gsub("'") { "\\'" }

    ______________________________________________________________________


-- gotoken

PS. Hokkaido island, whare I live in, doesn't have the rainy season. 
    It is very comfortable today :)

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