[−][src]Trait proc_macro_roids::FieldExt

pub trait FieldExt {
    fn type_name(&self) -> &Ident;

    fn is_phantom_data(&self) -> bool;

    fn contains_tag<NS, Tag>(&self, namespace: NS, tag: Tag) -> bool
    where
        Ident: PartialEq<NS>,
        Ident: PartialEq<Tag>;

    fn tag_parameter<NS, Tag>(&self, namespace: NS, tag: Tag) -> Option<Meta>
    where
        NS: Display,
        Tag: Display,
        Ident: PartialEq<NS>,
        Ident: PartialEq<Tag>;

    fn tag_parameters<NS, Tag>(&self, namespace: NS, tag: Tag) -> Vec<Meta>
    where
        NS: Display,
        Tag: Display,
        Ident: PartialEq<NS>,
        Ident: PartialEq<Tag>;
}

Functions to make it ergonomic to inspect Fields and their attributes.

Required methods

fn type_name(&self) -> &Ident

Returns the simple type name of a field.

For example, the PhantomData in std::marker::PhantomData<T>.

fn is_phantom_data(&self) -> bool

Returns whether the field is PhantomData.

Note that the detection is a string comparison instead of a type ID comparison, so is prone to inaccurate detection, for example:

  • use std::marker::PhantomData as GhostData;
  • use other_crate::OtherType as PhantomData;

fn contains_tag<NS, Tag>(&self, namespace: NS, tag: Tag) -> bool where
    Ident: PartialEq<NS>,
    Ident: PartialEq<Tag>, 

Returns whether a field contains a given #[namespace(tag)] attribute.

Parameters

  • namespace: The name() of the first-level attribute.
  • tag: The name() of the second-level attribute.

fn tag_parameter<NS, Tag>(&self, namespace: NS, tag: Tag) -> Option<Meta> where
    NS: Display,
    Tag: Display,
    Ident: PartialEq<NS>,
    Ident: PartialEq<Tag>, 

Returns the parameter from #[namespace(tag(parameter))].

Parameters

  • namespace: The name() of the first-level attribute.
  • tag: The name() of the second-level attribute.

Panics

Panics if there is more than one parameter for the tag.

fn tag_parameters<NS, Tag>(&self, namespace: NS, tag: Tag) -> Vec<Meta> where
    NS: Display,
    Tag: Display,
    Ident: PartialEq<NS>,
    Ident: PartialEq<Tag>, 

Returns the parameters from #[namespace(tag(param1, param2, ..))].

Parameters

  • namespace: The name() of the first-level attribute.
  • tag: The name() of the second-level attribute.
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Implementations on Foreign Types

impl FieldExt for Field[src]

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Implementors

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