I have an alternative suggestion: you can put an expression string in appropriate C# or VB.NET program text, build it using CodeDOM (present compilation errors if any), load the resulting assembly in an Application Domain, execute the method containing the expression, if required, present the result (in your original Application Domain of you UI), delete the Application Domain. It works very quickly, and those compilers are a part of .NET Framework, they are always available to the user and are invoked via CodeDOM.
Also, this way is very, very reliable, it relies on available well debugged and tested compilers and CLR.
I provided detailed explanations and further referenced in my past answers:
code generating using CodeDom[
^],
Create WPF Application that uses Reloadable Plugins...[
^].
—SA