Struct FieldsHelper

pub struct FieldsHelper<'f, T: FieldInfo> { /* private fields */ }

Utility struct to work with Fields

Implementations

impl<'f, T: FieldInfo> FieldsHelper<'f, T>

pub fn new(fields: &'f Fields<T>) -> Self

Builds a new FieldsHelper

pub fn filtering<P>(self, predicate: P) -> Self

where P: Fn(usize, &T) -> bool + 'f,

Remove all fields f for which predicate(&f) returns false. This method operates in place, visiting each element exactly once in the original order, and preserves the order of the retained elements.

pub fn with_attributes<P>(self, predicate: P) -> Self

where P: Fn(usize, &T) -> Option<TokenStream> + 'f,

Adds an arbitrary number of attributes to each field.

pub fn extra_default_fields<'a>( self, fields: impl IntoIterator<Item = &'a Ident>, ) -> Self

Includes additional default fields by including field1: Default::default(), field2: Default::default(),

It’s only used on named fields, but ignored for tuples.

pub fn extra_fields<'a>( self, fields: impl IntoIterator<Item = &'a Ident>, ) -> Self

Includes additional fields by including field1: field1, field2: field2,

It’s only used on named fields, but ignored for tuples.

pub fn extra_fields_with<'a>( self, fields: impl IntoIterator<Item = (&'a Ident, impl ToTokens)>, ) -> Self

Includes additional fields by including field1: expr1, field2: expr2.

It’s only used on named fields, but ignored for tuples.

pub fn ignore_extra<'a>( self, ignore_extra: impl IntoIterator<Item = &'a Ident>, ) -> Self

Ignore extra fields by including , field1: _ , field2: _ at the end.

It’s only used on named fields, but ignored for tuples.

pub fn ignore_all_extra(self, ignore_all_extra: bool) -> Self

Wether to include , .. at the end or not, defaults to false.

pub fn include_all_default(self, include_all_default: bool) -> Self

Wether to include , ..Default::default() at the end or not, defaults to false.

pub fn include_visibility(self, include_visibility: bool) -> Self

Wether to include the visibility at the beginning or not, defaults to false.

pub fn include_wrapper(self, include_wrapper: bool) -> Self

Wether to include the wrapper (curly braces for named fields, parenthesis for tuples), defaults to true.

pub fn left_collector<C>(self, left_collector: C) -> Self

where C: FnMut(usize, &T) -> TokenStream + 'f,

Specifies the left collector. It’s only used with named fields.

Defaults to FieldsCollector::ident

pub fn right_collector<C>(self, right_collector: C) -> Self

where C: FnMut(usize, &T) -> TokenStream + 'f,

Specifies the right collector.

Defaults to FieldsCollector::ty

pub fn is_empty(&self) -> bool

Checks if there’s no fields

pub fn into_vec(self) -> Vec<&'f T>

Takes the inner fields

pub fn collect(self) -> TokenStream

Collects the fields.

Examples

If using the default collectors on a Struct:

{
    field_1: String,
    field_2: i32,
}

If using FieldsCollector::ident right collector on a Struct:

{
    field_1: field_1,
    field_2: field_2,
}