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by scns 1520 days ago
Have you tried writing a DSL in Kotlin?
1 comments
PaulHoule 1520 days ago
Internal or external?

I think Java is just fine for internal DSLs, see

https://www.jooq.org/

jooq embeds a Turing complete programming language because it supports Procedural SQL.

I was also hacking on this project

https://github.com/paulhoule/ferocity/

which was about making Java homoiconic. Namely in ferocity you can write

   Expression<String> literal = of("Hello World");
   Expression<byte[]> expression = getBytes(literal);
and then

   expression.asSource() = '"Hello World".getBytes()'
   expression.evaluate() = {72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100}
the evaluation is done with the primitive interpreter strategy of evaluating all of the arguments of the function then calling the function, ...

I got far enough on that project that I discovered a bunch of things like the expression language has extensions over the real Java language pretty naturally for instance if you have a quote function like the quote in LISP you can write programs in the extended language to process syntactic macros.

I convinced myself that the idea is sound and got started on bootstrapping it by building a partial implementation (ferocity0) and code generator to make stubs out of the standard library plus a persistent collections library because that is pretty helpful for building the DSL, then write ferocity1 in ferocity0 wherever it could eliminate boilerplate (like the 8 primitive types.)

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