Trait FieldsExt 

pub trait FieldsExt {
    // Required methods
    fn is_named(&self) -> bool;
    fn is_unnamed(&self) -> bool;
    fn is_unit(&self) -> bool;
    fn as_named(&self) -> Option<&FieldsNamed>;
    fn as_unnamed(&self) -> Option<&FieldsUnnamed>;
    fn exists(&self, key: &FieldKey) -> bool;
    fn get(&self, key: &FieldKey) -> Option<&Field>;
    fn keyed(&self) -> impl Iterator<Item = (FieldKey, &Field)>;
    fn span(&self) -> Span;
}

Extension methods for types that contain syn::Fields.

Provides variant predicates (is_named, is_unnamed, is_unit), conversions (as_named, as_unnamed), and field lookup via FieldKey.

Implemented for syn::Fields, syn::ItemStruct, syn::DataStruct, and syn::Variant.

Examples

use zyn::ext::{FieldsExt, FieldKey};

#[zyn::element]
fn my_element(fields: zyn::Fields) -> zyn::TokenStream {
    if fields.is_named() {
        let f = fields.get(&"id".into());
    }
    // ...
}

Required Methods

fn is_named(&self) -> bool

Returns true if the fields are named (struct { a: T, b: U }).

fn is_unnamed(&self) -> bool

Returns true if the fields are unnamed (tuple (T, U)).

fn is_unit(&self) -> bool

Returns true if there are no fields (unit struct).

fn as_named(&self) -> Option<&FieldsNamed>

Returns the inner syn::FieldsNamed if the fields are named.

fn as_unnamed(&self) -> Option<&FieldsUnnamed>

Returns the inner syn::FieldsUnnamed if the fields are unnamed.

fn exists(&self, key: &FieldKey) -> bool

Returns true if a field matching the given FieldKey exists.

fn get(&self, key: &FieldKey) -> Option<&Field>

Returns the first field matching the given FieldKey, or None.

fn keyed(&self) -> impl Iterator<Item = (FieldKey, &Field)>

Returns all fields as (FieldKey, &Field) pairs.

Named fields yield FieldKey::Named, unnamed fields yield FieldKey::Index, and unit fields yield an empty vec.

Examples

use zyn::ext::{FieldsExt, FieldKey};

for (key, field) in fields.keyed() {
    println!("{}: {:?}", key, field.ty);
}

fn span(&self) -> Span

Returns the span of the fields.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl FieldsExt for Fields

fn is_named(&self) -> bool

fn is_unnamed(&self) -> bool

fn is_unit(&self) -> bool

fn as_named(&self) -> Option<&FieldsNamed>

fn as_unnamed(&self) -> Option<&FieldsUnnamed>

fn exists(&self, key: &FieldKey) -> bool

fn keyed(&self) -> impl Iterator<Item = (FieldKey, &Field)>

fn get(&self, key: &FieldKey) -> Option<&Field>

fn span(&self) -> Span

impl FieldsExt for Variant

fn is_named(&self) -> bool

fn is_unnamed(&self) -> bool

fn is_unit(&self) -> bool

fn as_named(&self) -> Option<&FieldsNamed>

fn as_unnamed(&self) -> Option<&FieldsUnnamed>

fn exists(&self, key: &FieldKey) -> bool

fn keyed(&self) -> impl Iterator<Item = (FieldKey, &Field)>

fn get(&self, key: &FieldKey) -> Option<&Field>

fn span(&self) -> Span

impl FieldsExt for DataStruct

fn is_named(&self) -> bool

fn is_unnamed(&self) -> bool

fn is_unit(&self) -> bool

fn as_named(&self) -> Option<&FieldsNamed>

fn as_unnamed(&self) -> Option<&FieldsUnnamed>

fn exists(&self, key: &FieldKey) -> bool

fn keyed(&self) -> impl Iterator<Item = (FieldKey, &Field)>

fn get(&self, key: &FieldKey) -> Option<&Field>

fn span(&self) -> Span

impl FieldsExt for ItemStruct

fn is_named(&self) -> bool

fn is_unnamed(&self) -> bool

fn is_unit(&self) -> bool

fn as_named(&self) -> Option<&FieldsNamed>

fn as_unnamed(&self) -> Option<&FieldsUnnamed>

fn exists(&self, key: &FieldKey) -> bool

fn keyed(&self) -> impl Iterator<Item = (FieldKey, &Field)>

fn get(&self, key: &FieldKey) -> Option<&Field>

fn span(&self) -> Span

Implementors