So, You Want to Write Your Own Language?

These are good suggestions, Walter. Let me add a couple more.

Always think of your language as a compiled language even if you start out just writing an interpreter. Otherwise you are likely to add features that are very difficult to compile efficiently.

If you're trying to design a language for accessibility -- ease of use by relatively inexperienced programmers -- be aware of the tradeoffs. For example, weak typing, such as automatic conversions between strings and integers, is commonly thought to make life easier for novices, but it can make it much harder to build large reliable systems -- and if your language is successful, it will wind up being used for large systems, regardless of its suitability for that purpose. Conversions from strings and integers to booleans have been a particular problem area. Make sure that comparison operators are transitive and equality is an equivalence relation -- and if you don't know what those terms mean, you need to study programming language design before you attempt it yourself.

Even if D is a lot better than Rust, Go or others about the style, I am amazed it is a concern for the author. Besides that, good advices to a candidate language author.