From: Peter Marks <petertmarks@...>
Date: 2008-04-05T08:56:56+09:00
Subject: Re: Using a string as executable code

Phillip Gawlowski wrote:
> And a question you might want to ask yourself: Do I want to be starring
> on DailyWTF as "the developer before me"?

Haha, point taken. I'm not familiar with metaprogramming or marshall. 
I'm looking into both.


ara.t.howard wrote:
did you read my code?

I did, but I must not understand all of it. Sorry.


ara.t.howard wrote:
> why don't you spell out your exact problem and we can show you how.

My db schema has a 'templates' table, a 'fields' table as well as a 
'template_fields' join table that connects 'fields' to 'templates'.

'fields' needs to contain information to produce a customized text 
string for a particular object. Intuitively, I thought I needed to store 
string generating code as a string in 'fields' and execute it against my 
object. It was suggested I could do that like this:

person.instance_eval field.code

I use the resulting string and the field's 'name' to assemble a hash for 
each field connected to a template:

      rehash = {}
      for field in template.fields
        rehash[field.name] = person.instance_eval field.code
      end

I then use the hash of generated strings and field names for a find and 
replace function.
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