Enum ConvertSpec 

pub enum ConvertSpec {
    PrebindgenFn(Ident),
    Trait {
        repr: Type,
        fallible: bool,
    },
}

Declares a type’s canonical single-value conversion: how one value of the type crosses the boundary wherever a single value is needed — as a parameter or return, inside Option<_> / Vec<_> / the Result<T, E> success position, as a data_class field. Each direction takes one ConvertSourceDecl:

.convert(convert!(Millis)
    .input(fun!(millis_from_long))   // fn(u64) -> Millis    (wire → rust)
    .output(fun!(millis_value))      // fn(&Millis) -> u64   (rust → wire)
    .valid_range(0u64..=86_400_000)) // rejects invalid values; Option uses a niche
.convert(convert!(Celsius).input(from!(i32)).output(into!(i32)))
.convert(convert!(Label)
    .input(try_from!(String).with(path!(crate::label_in)).error(ty!(String)))
    .output(into!(String).with(path!(crate::label_out))))

The foreign surface derives from the conversion’s other-side type (u64 ⇒ Kotlin ULong / C uint64_t) — nothing is stated verbatim. valid_range and valid_values declare the legal subset of a scalar representation. Generated converters validate the subset, and adapters may reuse values outside it as allocation-free Option/Result markers; exclude_values reserves holes in an otherwise legal domain. A try_ source’s Err routes to the caller’s error handler. Conversion fns may live in the flat crate or in a helper crate whose item stream is chained into the same prebindgen_flat::Flat::builder parse; generated calls qualify each function with its origin crate.

Distinct from the expand_param! / expand_return! boundary decls: those reshape a function boundary into multiple leaves (variants in / fields out), while convert! defines the type’s one-value form used everywhere else. A type may declare both — expansion wins at the fn boundaries where it is declared; the conversion serves every other position. The method names differ deliberately: converters are direction-things (input also serves callback returns, output also serves callback arguments), while expansion decls are position-things. One direction’s conversion source — where the conversion code comes from, the lowered form of a ConvertSourceDecl.

Variants

PrebindgenFn(Ident)

A #[prebindgen] fn (flat or helper crate): the representable type and fallibility are read from its registry signature at lookup time.

Trait

A core::convert trait impl; the representable type is stated explicitly (there is no signature to read). fallible selects TryInto (the associated Error routes to the caller’s error handler) vs Into.

Fields

repr: Type

fallible: bool

Implementations

impl ConvertSpec

pub fn describe(&self) -> String

One-line human description of the source kind (report use).

Trait Implementations

impl Clone for ConvertSpec

fn clone(&self) -> ConvertSpec

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.