Designing Fluent interface methods

Question

I am trying to write a DSL

I have methods that return strings but if I want to combine the strings I need to use a + symbol but I would like to call the methods together but I'm unsure how to achieve it

I have methods at the moment such as

MyStaticClass.Root() MyStaticClass.And() MyStaticClass.AnyInt() which return strings

I would like to be able to do

Root().And().AnyInt() which result in a string

Answer 1

The methods should return a wrapper class. The methods are also instance methods of the wrapper class. Example:

class Fluent
{
     private string _value;
     public Fluent And()
     {
         this._value += "whatever";
         return this;
     }
     public Fluent AnyInt()
     {
         this._value += "42";
         return this;
     }
     public override string ToString() { return _value; }
}

You could also define an implicit or explicit conversion from Fluent to string, rather than (or in addition to) the ToString() override.

Also, for production code, I'd use a string builder to avoid many calls to Concat.