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Comment by KTSnowy | Hacker News Reader

I know about GnuCOBOL, but both projects have different goals and ideals.

Otterkit compiles to C#, and GnuCOBOL compiles to C. The two are meant for different use cases. You wouldn't use a huge C program in a .NET backend, it would be a pain to make it work correctly and difficult to maintain.

GnuCOBOL also doesn't support quite a bit of COBOL's features. It only supports the procedural part of the language, and that is only a small part of it compared to the object oriented side of COBOL. Otterkit will support both, and the new 2022 standard.

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> Otterkit compiles to C#

Is it really a transpiler? Why not directly compile to CIL?

> I'm sure that most people are not aware that COBOL has generics

But this is only in the more recent standards, isn't it? I guess that 95% of existing Cobol applications still use the 1974 standard version.

> Why not directly compile to CIL?

This was asked and answered on reddit [0]:

> Exactly, there's no way that we could optimize the IL better than the dotnet compiler, so we chose to emit C# text and let the dotnet compiler do the optimization for us.

> This also makes it a lot simpler to generate code, without having to deal with the lower level IL.

[0]: https://old.reddit.com/r/csharp/comments/1074jdj/otterkit_a_...

JFYI, optimizations performed by C# compiler are not that great. They are present but their extent is pretty limited.

Actually I like it better when COBOL gets transpiled to C# and not IL but for another reason. COBOL -> C# pathway allows migration to something a bit more modern than COBOL itself. This may be crucial for some projects.

> Is it really a transpiler? Why not directly compile to CIL?

The end result of running Otterkit will be an executable or a C# DLL, so compiler would still be the most accurate word to describe it. If it stopped at the translation stage it would be a transpiler.

We're compiling to C# source text so that we can take advantage of the dotnet compiler optimizations. Otterkit calls the dotnet compiler after translating to C#.

> advantage of the dotnet compiler optimizations

That's mostly constant folding and a bit of peephole optimization; the CLI JIT or AOT compilers do most optimizations on the CIL level.

> so compiler would still be the most accurate word to describe it

Well, you do a source-to-source translation from Cobol to C#. The terminology is fuzzy, but usually we call it a transpiler if the output is yet another high-level programming language. But who cares.

If it is of any interest: In 2022, an announcement was posted to the GCC mailing list introducing a prototype implementation of a COBOL frontend to GCC, which would in theory compile COBOL directly to a target machine of choice.

Mind you, I haven't actually tested it myself.

Link: https://gcc.gnu.org/pipermail/gcc/2022-March/238408.html

Thanks for the answer. Looking forward for your project success!

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