From: Wybo Dekker <wybo@...>
Date: 2005-08-10T20:46:29+09:00
Subject: Re: passing a method

Patrick Gundlach and Devin Mullans wrote:

 > @t = ''
 > def bye
 >   @t << 'bye'
 > end
 > def hello
 >   @t << 'hello'
 > end
 > def doit(f)
 >   send f
 > end
 > doit(:hello)
 > doit(:bye)
 > doit(:hello)
 > puts @t

That's exactly what I needed. Thanks!

As for daniel's question:

 > Why do you want to do this?

and

 > This is a rather poor example, since the above three lines
 > could just as well be written like this:

 >   hello
 >   bye
 >   hello

Of course, that's because an exmaple should be short.
My actual code is an initializer for my scripts. I find myself all the
time re-inserting, in many scripts, code to test if executables are
available, code to read rc-files, to handle options, and more. I want to
put most of that stuff in a module which now contains an init method
using the above suggestion (for the last argument):

# program initializer:
# 1. check if all needed executables (in _needed_) are available
# 2. set the defaults (values of _defaults_) for
#    option- and rc-variables (keys of _defaults_)
# 3. read the standard rc-files
# 4. handle the options, as defined in the _optionproc_ method
# 5. if @rc appears to be defined, read it as an rc-file

def init(needed,defaults,option_handler)
   @rcfiles = [] # collect names for a report in case @verbose is true

   # set defaults:
   defaults.each do |k,v|
      eval("@#{k} = #{v || 'nil'}")
   end

   # check if all needed executables (in _needed_) are available
   check_execs(needed)

   # run all standard rc-files
   read_rc_files(defaults.keys)

   # handle options
   send option_handler

   # in case a --rc option was used, read its argument as an rc-file:
   read_rc_file(@rc,defaults.keys)

   # if the --verbose option was used, report rc-files read:
   if @verbose
      if @rcfiles.size > 0
         puts "These rc files were read:",@rcfiles.join("\n")
      else
         puts "No rc files were read"
      end
   end
end

-- 
Wybo