I've written an Object Pascal (the current incarnation that Delphi/FreePascal uses) compiler/transpiler for Object Pascal->JavaScript and yes, it's great language for compiler writers because the language makes the job of the compiler so easy. You have to really go out of your way to make the compilation slow, and there aren't a lot of undefined behaviors or other gotchas that are hard to navigate. Also, I wrote it in Delphi. :-)