Enum PathStep 

pub enum PathStep {
    Call {
        ident: Ident,
        optional: bool,
        owned: bool,
    },
    Field {
        ident: Ident,
        optional: bool,
    },
}

One step of a leaf’s UnfoldLeaf::path — how to get from the value reached so far to the next one.

A step is typed rather than a bare ident because a single path may mix the two: an expand_return!(T).fields(fields!(t_to_struct)) leaf calls the value-form accessor, reads a struct field, and may then call that field type’s own accessor — Call(t_to_struct), Field(key_expr), Call(keyexpr_as_str). LeafSource still says what kind of leaf sits at the end of the path; the steps say how it is reached.

Each step also records whether it is optional — its accessor returns Option<…>, or its field is typed Option<…>. A true on a step before the last makes it a nullable nesting step: the emitter matches on it and the None arm short-circuits the whole leaf to null. The flag is carried rather than re-derived so both kinds answer the question the same way and the emitter needs no type walk (an accessor’s Option was already peeled where the step was built).

Variants

Call

Call a #[prebindgen] accessor on the value reached so far: source_module::f(&value).

Fields

ident: Ident

optional: bool

owned: bool

Whether the value this call yields (its return with any Option peeled) is owned rather than a borrow — f(..) -> T / -> Option<T> against -> &T / -> Option<&T>.

Only an OPTIONAL step’s payload can reach an emitter as a bare binding, so this is only ever consulted there: what a Some arm binds is the accessor’s own value, and everything downstream of it — the next step’s receiver, the value form’s argument — needs to know whether it may be moved or has to be borrowed. Recorded here, at the one place the signature is in hand, because deriving it later from the path alone is not possible.

Field

Read a struct field of the value reached so far: value.f.

Fields

ident: Ident

optional: bool

Implementations

impl PathStep

pub fn call(ident: Ident, optional: bool, owned: bool) -> Self

An accessor call step. owned says whether its (Option-peeled) return is an owned value rather than a borrow — see Self::Call::owned.

pub fn yields_owned(&self) -> bool

Whether the value this step yields is owned. A field read composes as &(e).f, so it is a borrow by construction.

pub fn field(ident: Ident, optional: bool) -> Self

A struct-field read step.

pub fn ident(&self) -> &Ident

The step’s ident, whichever kind it is.

pub fn is_optional(&self) -> bool

Whether the step yields an Option — a nullable nesting step when it is not the last on the path.

pub fn is_plain_field(&self) -> bool

Whether the step is a plain (non-optional) field read — a path made only of these renders as value.a.b, needing no nesting match.

pub fn is_field(&self) -> bool

Whether the step is a field read, Option or not.

Trait Implementations

impl Clone for PathStep

fn clone(&self) -> PathStep

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PathStep

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for PathStep

impl PartialEq for PathStep

fn eq(&self, other: &PathStep) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for PathStep