StructDefinition

std::meta::struct_def contains methods on the built-in StructDefinition type. This type corresponds to struct Name { field1: Type1, ... } items in the source program.

Methods

add_attribute

add_attribute

fn add_attribute<let N: u32>(self, attribute: str<N>) {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L3-L5}}

Adds an attribute to the struct.

as_type

as_type

fn as_type(self) -> Type {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L10-L12}}

Returns this struct as a type in the source program. If this struct has any generics, the generics are also included as-is.

generics

generics

fn generics(self) -> [Type] {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L21-L23}}

Returns each generic on this struct.

Example:

#[example]
struct Foo<T, U> {
    bar: [T; 2],
    baz: Baz<U, U>,
}

comptime fn example(foo: StructDefinition) {
    assert_eq(foo.generics().len(), 2);

    // Fails because `T` isn't in scope
    // let t = quote { T }.as_type();
    // assert_eq(foo.generics()[0], t);
}

fields

fields

fn fields(self) -> [(Quoted, Type)] {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L28-L30}}

Returns each field of this struct as a pair of (field name, field type).

has_named_attribute

has_named_attribute

fn has_named_attribute(self, name: Quoted) -> bool {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L15-L17}}

Returns true if this struct has a custom attribute with the given name.

module

module

fn module(self) -> Module {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L33-L35}}

Returns the module where the struct is defined.

name

name

fn name(self) -> Quoted {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L38-L40}}

Returns the name of this struct

Note that the returned quoted value will be just the struct name, it will not be the full path to the struct, nor will it include any generics.

set_fields

set_fields

fn set_fields(self, new_fields: [(Quoted, Type)]) {}

^{_{Source code: noir_stdlib/src/meta/struct_def.nr#L47-L49}}

Sets the fields of this struct to the given fields list where each element is a pair of the field's name and the field's type. Expects each field name to be a single identifier. Note that this will override any previous fields on this struct. If those should be preserved, use .fields() to retrieve the current fields on the struct type and append the new fields from there.

Example:

// Change this struct to:
// struct Foo {
//     a: u32,
//     b: i8,
// }
#[mangle_fields]
struct Foo { x: Field }

comptime fn mangle_fields(s: StructDefinition) {
    s.set_fields(&[
        (quote { a }, quote { u32 }.as_type()),
        (quote { b }, quote { i8 }.as_type()),
    ]);
}