How can I allow user to customize the functionality of program at runtime? (not using runtime code compilation)

Question

Using .NET Framework 4.0 what features are available that would allow to accomplish something very modular and user customizable, like depicted in this XML.  Where I define specific base operations like Get() and Put() methods that operate on strings. 
And allow the user to add and remove those or mix and match them in a way that they basically design their own run time functionality that suits them.  So they just create their own 'Operation' and fill it with the operations they want to perform on some
incoming data type, in this case it is a string - with substring and insert methods. 
EDIT - Assuming end user is non programmer and Dynamic Code compilation is not an option.  I have an idea maybe using dynamic keyword, but not sure if it makes what i suggest possible.
<Operation Name="GetValues">
  <Get id=123"  FromIndex="2" ToIndex="23"/>
  <Get id="234"  FromIndex="3" ToIndex="5"/>
   <Output Path="C:\" Filename="testOut.txt" Append="true">
     <Format>
          <Result id="123"/> , <Result id="234"/>
     </Format>
   </Output>
</Operation>
<Operation Name="InsertValue">
  <Put AtIndex="5">stringtoinsert</Put>
  <Put AtIndex="36">anotherstringtoinsert</Put>
</Operation>

Answer 1

Hi sjs1978,
I am not familiar with dynamic code, and I made a research about it.
>> I'm aware of dynamic code compilation, but that requires user to input pieces of code.
Did you try to store the pieces of code into a file and call the code when the dynamic code compilation requires user to input code?
In addition, I found links about using code provider to compile a source file, and the links below might be useful to you.
# Dynamic Source Code Generation and Compilation
https://msdn.microsoft.com/en-us/library/650ax5cx(v=vs.110).aspx
# CSharpCodeProvider Class
https://msdn.microsoft.com/en-us/library/microsoft.csharp.csharpcodeprovider(v=vs.110).aspx
# Is it possible to dynamically compile and execute C# code fragments?
http://stackoverflow.com/questions/826398/is-it-possible-to-dynamically-compile-and-execute-c-sharp-code-fragments
Best Regards,
Tony
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