From: John Maclean <info@...>
Date: 2006-02-26T03:19:11+09:00
Subject: comments of less.rb appreciated

I've had a look at /usr/share/doc/ruby-1.8.4/sample/less.rb and made
some comments on the processes where I could. It came with my repos
installation of Ruby. Can someone point me in the right direction here,
as there a a number of things that I'm not familar with or
understand....

#!/usr/bin/ruby
# there isn't a single def foo ... end method here - why?
# also how come this hasn't been turned into a class?
# is that because that there is no need for one?
# also why the use of GLOBAL VARIABLES? I thought that they are not
from the "church of good design"

# gobal vars to hard-code where these programs are... assuming a
Unix-based system # it was weired because the path was initially set
to /usr/local/bin/ # which did not work
# i personally think it's better to use a ruby equivalent of `which
less` to find out where the command is # rather than hard coding it in
this way ZCAT = "/usr/bin/zcat"
LESS = "/usr/bin/less"
# funny how you can call ruby less.rb with --help

# dunno about this class or method
FILE = ARGV.pop

# ah, i think that this may be exception handling.
# if no arguments from command line *OPTION* is zero
# otherwise out an empty string at the end of the filename??
OPTION = (if ARGV.length == 0; "" else ARGV.join(" "); end)

# we are grepping for stuff...
# a file that ends in Z or gz - these are compressed files
if FILE =~ /\.(Z|gz)$/

  # what is  *%s*? 
  #   - is it a string that we come across when we are grepping through
the files?

  # see `ri kernel.format` for the *format* method
  # "Argument is a string to be substituted"
  # i think it works with sprintf

  # run zcat on a compressed file _first_ then view it with less
  exec(format("%s %s | %s %s", ZCAT, FILE, LESS, OPTION))
  # otherwise there *is* no compressed file and we treat it differently
elsif FILE == nil
  #  
  exec(format("%s %s", LESS, OPTION))
else
  print(format("%s %s %s", LESS, OPTION, FILE), "\n")
  exec(format("%s %s %s", LESS, OPTION, FILE))
end
# end the `less`ing. i dont know why the use of the empty brackets
exit()

-- 
John Maclean
MSc (DIC)
07739 171 531