From: sto.mar@...
Date: 2012-08-17T23:03:04+09:00
Subject: Re: variable from array to function to array

Am 17.08.2012 14:15, schrieb Dave Castellano:
> The bigger picture...  I am saving multiple question templates in a
> array and need to store all the info (the question, the min and max
> ranges, the units of measure etc assoc with each question.  The
> associated info is used to build the question ... eg in question one,
> need to pass 20,40 to number_range(min,max)  and use the returned value
> as u.

Ok... :)

First: did you consider using a templating system for your
"question templates"? You could avoid the lambdas;
instead, you provide a template as a simple string that gets
evaluated later when the needed values are known.

Second: Instead of using nested arrays I would put all the
question-generating functionality into a class.

Assuming the structure of your questions is always the same,
below is one possible way to do it:


require 'erb'

class Question

   attr_reader :unit

   def initialize(text, range, unit)
     @text = ERB.new(text)
     @range = range
     @unit = unit
   end

   def val
     rand(@range)
   end

   def to_s
     @text.result(binding)
   end
end

questions = [
   Question.new('A slide is placed <%= val %> <%= unit %>...',
                20..40, 'cm'),
   Question.new('An image is in focus <%= val %> <%= unit %>...',
                10..15, 'mm')
]

questions.each {|q| puts q }
questions.each {|q| puts q }  # results in different values


*BUT:*

- Can't you simply include the unit in the text part?
- Do you really need to have the same question with
   different values in the same run of your program?

How about:

questions = [
   "A slide is placed #{rand(20..40)} cm...",
   "An image is in focus #{rand(10..15)} mm..."
]
questions.each {|q| puts q }


> def number_range(min,max)
>    min + rand(max - min + 1)  **Thanks!
> end
>
> array =[
> [ lambda {|u,u_unit| "A slide is placed #{u} #{u_unit} to the left of a
> lens...", 20, 40, "cm"],
> [ lambda {|v,v_unit| "An image is in focus #{v} #{v_unit} to the right
> of a...", 10, 25, "mm],
> [....
> ]
>
> puts array[n][variable returned from number_range method]


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