From: RichardOnRails <RichardDummyMailbox58407@...>
Date: 2010-12-29T10:55:21+09:00
Subject: Re: How to DRY code to prompt for parameters

On Dec 23, 10:05 am, "Abinoam Jr." <abin...@gmail.com> wrote:
> Symbol? Even better.
>
> Mixing some ideas from the Josh code we have...
>
> Remember... as Josh said you shouldn't rely on Hash items order. (this
> code does this :/ )
> Hashes are not ordered by nature.
>
> http://www.pastie.org/1400695
>
> On Thu, Dec 23, 2010 at 11:10 AM, RichardOnRails
>
> <RichardDummyMailbox58...@uscomputergurus.com> wrote:
> > On Dec 22, 11:55 pm, Josh Cheek <josh.ch...@gmail.com> wrote:
> >> [Note:  parts of this message were removed to make it a legal post.]
>
> >> On Wed, Dec 22, 2010 at 10:10 PM, RichardOnRails <
>
> >> RichardDummyMailbox58...@uscomputergurus.com> wrote:
> >> > I pasted code to prompt for a couple of parameter-values at
> >> >http://www.pastie.org/1399710.
>
> >> > Running this code under SciTE produces, for example:
> >> > Getting parms
> >> >        Account Number: 123
> >> >        Report  Period: 456
> >> > Showing parms
> >> >        @acct_num = 123
> >> >        @acct_period = 456
>
> >> > It is excessively verbose because I couldn't figure out how to use
> >> > meta-language to specify the parameter target names.  That led me to
> >> > using case statements to accept input values and then populate the
> >> > instance variables.
>
> >> > Can anyone suggest how I can use the instance variables as targets in
> >> > lieu of the case statements?  BTW, I want to get this working with
> >> > meta-programming.  I don't want to use some other approach, such as a
> >> > plug-in for getting arguments.
>
> >> > Thanks in Advance,
> >> > Richard
>
> >> I think you are looking for instance_variable_set and instance_variable_get.
> >> I don't really understand all the decisions you made, such as the array of
> >> hashes, to me that implies you want ordered hashes, but are on 1.8 (If you
> >> are in Rails, you have ActiveSupport loaded, and it provides an OrderedHash
> >> class that you can use) since they are ordered in 1.9. To get around that, I
> >> just made it an Array of Structs. Anyway, hopefully you can get out of this
> >> whatever you're trying to do.
>
> >> class X
>
> >>   def initialize
> >>     param = Struct.new :human_readable , :ivar
> >>     @rpt_parms = [
> >>       param.new( "Account Number" , "@acct_num"    ),
> >>       param.new( "Report  Period" , "@acct_period" ),
> >>     ]
> >>   end
>
> >>   def get_parms
> >>     @rpt_parms.each do |param|
> >>       print "\t#{param.human_readable}: "
> >>       instance_variable_set( param.ivar , gets.to_i ) # don't need to chomp,
> >> to_i will ignore the newline
> >>     end
> >>   end
>
> >>   def show_parms
> >>     @rpt_parms.each do |param|
> >>       value = instance_variable_get(param.ivar)
> >>       puts "\t#{param.human_readable} = #{value}"
> >>     end
> >>   end
>
> >>   def run
> >>     puts "Getting parms"
> >>     get_parms
> >>     puts "Showing parms"
> >>     show_parms
> >>   end
>
> >> end
>
> >> X.new.run
>
> >> I think you are looking for instance_variable_set and instance_variable_get.
> > That's also exactly the thing I needed!  Excellent!!
>
> >> To get around that, I just made it an Array of Structs.
> > Another responder did what I really wanted but was too stupid to do
> > is:
> >  @parms = {  "Account Name" => :acct_name,
> >              "Account Number" => :acct_num
> >           }   # etc.
>
> > Thanks very much for your insights.
> > Best wishes,
> > Richard
>
>

Thanks for your additional interest in my question. For my purposes,
the parameter-prompts should be presented in the same order that they
were fed to processor.  Also,  I want to employ this in future
programs I write,  so I also decided to modularize it. So following is
the bottom line, which I present inline here because Pastie barfed
when I tried to post it there. (I don't feel like debugging Pastie:
I've got enough to do!)

Best wishes,
Richard

## Test of new code under SciTE
>ruby TestParmHandler.rb
Getting parms
	Account Number: 123
	Report  Period: 456
Showing parms
	Account Number = 123
	Report  Period = 5456
>Exit code: 0

## Test program
# ParmHandlerUser.rb
# K:\_Projects\Ruby\_Ruby_Apps\ParmHandler

require 'ParmHandler.rb'

class ParmHandlerTester
  include ParmHandler
end

phu = ParmHandlerTester.new([
	  {"Account Number"		=> "@acct_num"},
	  {"Report  Period"		=> "@acct_period"}
	])
phu.run

## ParmHandler Module
# ParmHandler.rb
# Copy:	K:\_Utilities\ruby186-26_rc2\ruby\lib\ruby\site_ruby
# Original:	K:\_Projects\Ruby\_Ruby_Apps\ParmHandler

module ParmHandler
  def initialize rpt_parms
      @rpt_parms = rpt_parms
  end

  def get_parms
    @rpt_parms.each { |param|
	param.each { |parm_name, parm_var|
	    print "\t%s: " % parm_name
	    STDOUT.flush
	    instance_variable_set( parm_var , gets.chomp )
	}
    }
  end

  def show_parms
    @rpt_parms.each { |param|
	param.each { |parm_name, parm_var|
	  value = instance_variable_get(parm_var)
	  puts "\t%s = %s" % [parm_name, value.to_s]
	}
    }
  end

  def run
    puts "Getting parms"
    get_parms
    puts "Showing parms"
    show_parms
  end
end