From: "Abinoam Jr." <abinoam@...>
Date: 2010-12-24T00:05:35+09:00
Subject: Re: How to DRY code to prompt for parameters

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
<RichardDummyMailbox58407@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
>
>