Struct DynamicDefault 

pub struct DynamicDefault { /* private fields */ }

An application-supplied dynamic default with an explicit semantic revision, computed from earlier answers instead of declared statically.

Real interactive flows need context-dependent defaults — a field whose sensible default depends on how an earlier question was answered. The closure receives an EarlierAnswers view of the decoded answers that precede this field in the same scope chain and returns the default text, which then runs through the exact same kind / constraint / validator pipeline as any submitted answer, identically across interactive, file, and stdin collection.

Because closure semantics cannot be fingerprinted, the application declares an explicit revision string that enters the fingerprint in place of a static default value — exactly the FieldValidator revision contract: bump the revision whenever the computed defaults change, and previously rendered sheets are invalidated like any other semantic change. The closure itself never affects the fingerprint.

Dependency contract

Like a condition, a dynamic default may only depend on fields declared before its own field, in the same group or an enclosing one. Construction cannot introspect the closure to enforce this, so the walk order defines the failure behavior instead: the EarlierAnswers view resolves lookups against the answers decoded so far, and a later-declared, out-of-scope, unknown, unanswered, or inactive field simply reads as None. The closure must return a usable default for every combination of Nones it can observe.

Implementations

impl DynamicDefault

pub fn new( revision: impl Into<String>, compute: impl Fn(&EarlierAnswers<'_>) -> String + Send + Sync + 'static, ) -> Self

Create a dynamic default with a semantic revision and a compute closure that derives the default text from earlier answers.

pub fn revision(&self) -> &str

The semantic revision that participates in the fingerprint.

Trait Implementations

impl Clone for DynamicDefault

fn clone(&self) -> DynamicDefault

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DynamicDefault

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

Formats the value using the given formatter.

impl Eq for DynamicDefault

impl PartialEq for DynamicDefault

Equality compares the semantic revision only; the closure itself is not comparable, and the revision is the declared semantic identity.

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

Equality operator ==.

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

Inequality operator !=.