Metaprogramming and AST manipulation from Codon

[Clonkk]

Is there a way to build AST directly from Codon and resolve it at compile time (essentially metaprogramming / macros) ?

[arshajii]

Hi @Clonkk -- can you please give an example of what you'd like to do? While we don't (yet) have a way to access the AST directly from Codon, there are ways to get information about types etc. programmatically that, in combination with other features like decorators, can often accommodate "reflection-style" use cases.

[Clonkk]

I have 2 use-case essentially;

"standard" metaprogramming

Generating multiple functions at compile-time, reducing boiler plate code, implementing templates (code injection) are typical use-case.

Always practical to have on hand but I don't have an actual need for it.

Writing interpreters

Validating and interpreting AST at run-time.

Mapping some external AST onto Codon AST and check the Codon AST is correct or extract an error message.

Codon AST can generate LLVM IR. GraalVM IR + LLI can interpret it; this would make it possible to extend Codon to be both a JIT language and a statically compiled language.

Alternative to above use-case

Since Codon is largely inspired by Python, a typed Codon implementation of the Python AST module to be able to generate, validate and execute Python AST at Codon run-time would work just as well (would probably be slower and much more limiter).

The end goal being able to validate and execute a JIT compiled expression in a statically compiled binary