Struct synstructure::BindingInfo

pub struct BindingInfo<'a> {
    pub binding: Ident,
    pub style: BindStyle,
    // some fields omitted
}

Information about a specific binding. This contains both an Ident reference to the given field, and the syn &'a Field descriptor for that field.

This type supports quote::ToTokens, so can be directly used within the quote! macro. It expands to a reference to the matched field.

Fields

binding: Ident

The name which this BindingInfo will bind to.

style: BindStyle

The type of binding which this BindingInfo will create.

Methods

impl<'a> BindingInfo<'a>

pub fn ast(&self) -> &'a Field

Returns a reference to the underlying syn AST node which this BindingInfo references

pub fn pat(&self) -> Tokens

Generates the pattern fragment for this field binding.

Example

let di = syn::parse_derive_input(r#"
    enum A {
        B{ a: i32, b: i32 },
        C(u32),
    }
"#).unwrap();
let s = Structure::new(&di);

assert_eq!(
    s.variants()[0].bindings()[0].pat(),
    quote!{
        ref __binding_0
    }
);

pub fn referenced_ty_params(&self) -> Vec<&'a Ident>

Returns a list of the type parameters which are referenced in this field's type.

Caveat

If the field contains any macros in type position, all parameters will be considered bound. This is because we cannot determine which type parameters are bound by type macros.

Example

let di = syn::parse_derive_input(r#"
    struct A<T, U> {
        a: Option<T>,
        b: U,
    }
"#).unwrap();
let mut s = Structure::new(&di);

assert_eq!(
    s.variants()[0].bindings()[0].referenced_ty_params(),
    &[&(syn::Ident::from("T"))]
);

Trait Implementations

impl<'a> Debug for BindingInfo<'a>

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

Formats the value using the given formatter.

impl<'a> Clone for BindingInfo<'a>

fn clone(&self) -> BindingInfo<'a>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a> PartialEq for BindingInfo<'a>

fn eq(&self, other: &BindingInfo<'a>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &BindingInfo<'a>) -> bool

This method tests for !=.

impl<'a> Eq for BindingInfo<'a>

impl<'a> Hash for BindingInfo<'a>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where     H: Hasher,

Feeds a slice of this type into the given [Hasher].

impl<'a> ToTokens for BindingInfo<'a>

fn to_tokens(&self, tokens: &mut Tokens)

Write self to the given Tokens.