Suggestions for writing a programming language? [c

Question

What tips can you give a person who is looking to write a programming or script language? I am not worried about how to program nor design a compiler but how to develop one quickly using tools and code generators.

Last time i tried i coded it in c++ and the states and syntax took almost as long as writing the actual logic. I know the follow tools would help.

I was thinking i could generate c++ code and have gcc compile that. Using the tools above how long would you estimate it would take to write a program or script language?

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Variations on this question have been asked repeatedly, as far back as Learning to write a compiler. Here is an incomplete list of SO resources on the topic.

Answer 1

I'd strongly recommend looking at existing bytecode interpreters. If you can make your language fit into CIL (.NET) or Java (or even others such as Python or Parrot), you'll save yourself all the effort of making a workable supporting environment and can get on with experimenting with language concepts.

Answer 2

Dave Hanson, who with Chris Fraser spent 10 years building one of the world's most carefully crafted compilers, told me once that one of the main things he learned from the experience was not to try to write a compiler in C or C++.

If you want to develop something quickly, don't generate native code; target an existing virtual machine such as the CLR, JVM, or the Lua virtual machine. Generate code using maximal munch.

Another good option if you're writing an interpreter is just to use the memory management and other facilities of your underlying programming language. Parse to an AST and then interpret by tree walk of the AST. This will get you off the ground fast. Performance is not the greatest, but it's acceptable. (Using this technique I once wrote a PostScript interpreter in Modula-3. The first implementation took a week and although it later underwent some performance tuning, primarily in the lexer, it never had to be replaced.)

Avoid LALR parser generators; use something that saves your time, like ANTLR or the Elkhound GLR parser generator.

Answer 3

Any questions about compilers will have an answer "go read dragon book, read that book, this book..." on SO regardless of their content in a few minutes. So I skip that part (like I was telling in the first place). Reading these books to learn how to use the tools you want, is about as useful as reading about angular momentum to learn how to ride a bike.

So, to answer what you asked, without questioning your intention, I can easily recommend antlr and antlrworks for starters. You can generate your AST easily (where the real magic happens, I think) and debug your grammar visually. It generates a good portion of a working compiler for you.

If you know your stuff and want to have more control or don't like antlr, you can use lemon parser generator and ragel state machine compiler (have special support for lexing) together.

If you don't need too much performance and since you plan to generate C/C++ code, you can skip doing any optimizations yourself and leave that stuff to your C/C++ compiler.

If you can live with a slow runtime, you can further shorten your development effort just doing interpretation, since it is often easier to implement dynamic features this way.

Answer 4

I think everybody is missing one very important point.

WHY do you want to write a compiler / interpreter / parser etc.

This will seriously determine a lot of what you do.

I have worked on quite a few language implementations, some rather weird, some domain specific, some simply scripted progress through command environments (often where the command environment was later hidden). Each required different levels of skill.

Many books available. One I loved was a BYTE book : Threaded Interpreted Languages - bet it's out of print.

Simple script engines can be crafted with a few evening's thinking and a bit of trial and error.

But I bet there are online courses now that will save you a ton of time.