Conditional imports

Compiling and formatting this syntax also requires a compiler and formatter that support conditional import blocks.

Use #cfg in moon.pkg to select imports for a backend:

#cfg(target = "native")
import {
  "example/platform/native" @platform,
}

#cfg(not(target = "native"))
import {
  "example/platform/portable" @platform,
}

Both implementations can use the same alias because only one import is active for each backend. Unannotated import blocks apply to every backend.

Supported targets are wasm, wasm-gc, js, native, and llvm. Combine conditions with all(...), any(...), and not(...), or use true and false. For example, #cfg(any(target = "native", target = "js")) selects Native and JavaScript. Conditions also apply to import blocks ending in for "test" or for "wbtest".

Repeated imports within the same import kind produce a warning when their conditions overlap. They remain valid and keep their declaration order. Imports with disjoint conditions do not produce a duplicate warning.

Inactive imports do not add build dependencies. An active import from another module still requires a module dependency declaration. Import conditions do not change the package’s supported_targets setting.