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tinco, as with most programming language dilettantes I have a wishlist for my ultimate language, but I've never actually implemented one. Where would you sugges

tinco, as with most programming language dilettantes I have a wishlist for my ultimate language, but I've never actually implemented one. Where would you suggest I start? And where should I go after that?

tinco 14y ago
The first part is always making the list of features you want to have, these are the ones you value most and don't want to compromise on. You should write them down maybe hang them on your wall to remind yourself. Go through the list and try to find out if no features conflict with each other. That a language exists that has both features is usually a good sign. After that comes designing a grammar. How do you want to express the features? This is a fun part. I start by selecting a small program I think should be easy to implement in my language, for example a coffee machine, a small web application, a mathematical algorithm (like fibonacci). Find some you think should be written in your language, and then just do it. Be very careful in that everything you want to express is actually expressed in an unambiguous way. When you think you got the idea of your language down, now you write it down formally. This is where it gets a little complex so I'm not going to fully explain it (you can mail me when you're at that point @tinco.nl) but the basic idea is that you learn EBNF, and pick a lexer/parser generator (there's multiple in every language, even javascript). Depending on what features your language has this can be very hard, Ruby for example can only be parsed and lexed at the same time so it requires much hand tweaking. Depending on the particulars of the language it doesn't really matter in which language the compiler is written, pick one as highlevel as you can. Compilation speed is only important once you have a reference implementation. Then a rather difficult step, the code generator. It takes your AST and turns it into executable code. For CoffeeScript this means turning it into Javascript. For C# it means turning it into CLR bytecode, for C it means turning it into x86 machine code. I recommend that as a target language you pick a language that is as close to your desired feature set as possible without conflicting with any of your features. A conflict here means either a lot of work to implement, or incurring a too big performance loss. Pick a low level one like LLVM or CLR bytecode if you need good performance. And then you're done. Now you have a reference implementation you can focus on making it run fast (by selecting a lower level target language / implementing optimizations) and on making a standard library.
- Scramblejams 14y ago
  Thanks for the guidance. If you ever do a release of your own handiwork, please let me know. Email's in my profile.

tinco 14y ago

The first part is always making the list of features you want to have, these are the ones you value most and don't want to compromise on. You should write them down maybe hang them on your wall to remind yourself. Go through the list and try to find out if no features conflict with each other. That a language exists that has both features is usually a good sign. After that comes designing a grammar. How do you want to express the features? This is a fun part. I start by selecting a small program I think should be easy to implement in my language, for example a coffee machine, a small web application, a mathematical algorithm (like fibonacci). Find some you think should be written in your language, and then just do it. Be very careful in that everything you want to express is actually expressed in an unambiguous way. When you think you got the idea of your language down, now you write it down formally. This is where it gets a little complex so I'm not going to fully explain it (you can mail me when you're at that point @tinco.nl) but the basic idea is that you learn EBNF, and pick a lexer/parser generator (there's multiple in every language, even javascript). Depending on what features your language has this can be very hard, Ruby for example can only be parsed and lexed at the same time so it requires much hand tweaking. Depending on the particulars of the language it doesn't really matter in which language the compiler is written, pick one as highlevel as you can. Compilation speed is only important once you have a reference implementation. Then a rather difficult step, the code generator. It takes your AST and turns it into executable code. For CoffeeScript this means turning it into Javascript. For C# it means turning it into CLR bytecode, for C it means turning it into x86 machine code. I recommend that as a target language you pick a language that is as close to your desired feature set as possible without conflicting with any of your features. A conflict here means either a lot of work to implement, or incurring a too big performance loss. Pick a low level one like LLVM or CLR bytecode if you need good performance. And then you're done. Now you have a reference implementation you can focus on making it run fast (by selecting a lower level target language / implementing optimizations) and on making a standard library.

Scramblejams 14y ago
Thanks for the guidance. If you ever do a release of your own handiwork, please let me know. Email's in my profile.