Plain english to conditions in ror??

Hi All,
       I wanna to do something like as:
1. Use will type plain English in text box like designation equals PM or
designation = PM.

2.Then i have to save this rule in DB and i have to made some function
to verify this rule.

3. My problem is that how to make if condition for following rule
dynamically.Cos in ROR i can say designation == 'PM'then fine but how i
will check that designation equals PM.

4.Means i have to make condition from plain english dynamically.

Please tell me ur suggestions.

Thanks
Varun

I would recommend that you create a DSL for your users. You can setup a mapping that abstracts away your domain specific names and allows for various types of rule creation. You need to guard/filter against code injection if you are eval-ing the rules directly.

Hope that helps.

Take a look at TreeTop. I'm not sure how complicated you want to get,
but it might be what you are looking for.
http://www.rubyinside.com/treetop-powerful-but-easy-ruby-parser-library-701.html

HTH