Import memory into Wasm compiled from Grain

[radkomih]

Hi there,
Is it possible to compile module written in Grain and produce Wasm module that looks similar to the one below?

• import host provided memory
• import host provided functions
• export linker specific globals

Type: wasm
Size: 210 B
Imports:
  Functions:
    "env"."ext_func": [] -> []
  Memories:
    "env"."memory": not shared (20 pages..)
  Tables:
  Globals:
Exports:
  Functions:
    "inter_func": [I32, I32] -> [I64]
  Memories:
  Tables:
  Globals:
    "__data_end": I32 (constant)
    "__heap_base": I32 (constant)

[ospencer]

Hiya! This was answered on Discord, but we figured we should post here as well! It's possible to import host-provided functions and export specific globals, but it's not currently possible to import a host memory. This is mostly a matter of how memory management works in WebAssembly at the moment. Grain programs need to manage the memory, and thus it's far more feasible for Grain programs to export a memory. This will definitely change as the wasm GC proposal matures.

There are some upcoming docs on how to import host-provided functions, but in the meantime you can see some examples of this in https://github.com/grain-lang/lunatic-gr.

It's certainly pretty low level at the moment, so please reach out on Discord if you need any help getting things working!