From: ara.t.howard@...
Date: 2006-01-16T09:53:55+09:00
Subject: Re: Passing functions as arguments

On Mon, 16 Jan 2006, Alex Polite wrote:

> I'm just starting out with ruby.
>
> I'm trying to make an array of arrays containing [a pattern, a string,
> a function]
>
> Patterns and strings went fine but when I put in a function ruby tries
> to eval it and complains about not getting right number of arguments.
>
> Is there any way to escape a method so that you can put it in a list
> or pass it as an argument to another function?
>
> pats = [
>        [/:BEGIN:(.*)/, "DTSTART", Df.datestr2time ],
>        [/:DUE:(.*)/,   "DUE", Df.datestr2time]
>       ]

yes.  but you don't need to, simply store the name of the method and use
'send':

   harp:~ > cat a.rb
   table =
    [%r/:BEGIN:(.*)/, "DTSTART", "datestr2time"],
    [%r/:DUE:(.*)/,   "DUE", "datestr2time"]

   #
   # mock-up
   #
   class Df
     def self::datestr2time string
       p string
     end
   end

   txt = <<-txt
     :BEGIN:
     :DUE:
   txt

   txt.each do |line|
     table.each do |dispatch|
       pat, string, method = dispatch
       if pat.match line
         Df::send method, string
       end
     end
   end


   harp:~ > ruby a.rb
   "DTSTART"
   "DUE"


regards.

-a
-- 
strong and healthy, who thinks of sickness until it strikes like lightning?
preoccupied with the world, who thinks of death, until it arrives like
thunder?  -- milarepa