Struct VariantBuilder 

pub struct VariantBuilder { /* private fields */ }

Builder for constructing Variant instances in const contexts.

This builder enables shorter derive macro output by providing a fluent API for constructing variants with default values for optional fields.

Example

use facet_core::{VariantBuilder, StructTypeBuilder, StructKind, Variant};

const VARIANT: Variant = VariantBuilder::new(
    "Foo",
    StructTypeBuilder::new(StructKind::Unit, &[]).build()
)
.discriminant(42)
.build();

Implementations

impl VariantBuilder

pub const fn new(name: &'static str, data: StructType) -> Self

Creates a new VariantBuilder with the required fields.

Parameters

• name: The name of the variant
• data: The struct type representing the variant’s fields

pub const fn unit(name: &'static str) -> Self

Creates a unit variant (no fields).

Example

VariantBuilder::unit("None").build()

pub const fn tuple(name: &'static str, fields: &'static [Field]) -> Self

Creates a tuple variant with the given fields.

Example

VariantBuilder::tuple("Some", &[FieldBuilder::new("0", T::SHAPE, 0).build()]).build()

pub const fn discriminant(self, discriminant: i64) -> Self

Sets the discriminant value for this variant.

Defaults to None if not called.

pub const fn attributes(self, attributes: &'static [VariantAttribute]) -> Self

Sets the attributes for this variant.

Defaults to an empty slice if not called.

pub const fn doc(self, doc: &'static [&'static str]) -> Self

Sets the documentation for this variant.

Defaults to an empty slice if not called.

pub const fn build(self) -> Variant

Builds the final Variant instance.

Trait Implementations

impl Clone for VariantBuilder

fn clone(&self) -> VariantBuilder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VariantBuilder

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

Formats the value using the given formatter.

impl Copy for VariantBuilder