So I made a simple scripting language in C# based on batch. I made it compile into a batch file since it is a scripting language it had no compiler. Is there any program out there where you can customize a programming language and compiler?

Is there any program out there where you can customize a programming language and compiler?

What exactly do you mean by "customize"?

In C# you could use extension methods Click Here, but I do not understand what you realy want.

I once whipped-up a quick scripting language with its interpreter written in C... Like everyone else, I'm not quite sure what your question is, exactly, but if you can have a mess-around with C# or another language and make a program which is an interpreter (rather than a translater-compiler-type-thing) then you'll have started making your own language with a more traditional approach.