Struct AttributeChain

Source

pub struct AttributeChain { /* private fields */ }

Expand description

A parsed Rust attribute expression made from a path root and zero or more dot calls.

Accepted roots are:

a path, such as RangeValidation::<_>.

Implementations§

Source §

impl AttributeChain

Source

pub fn parse_with_options( input: ParseStream<'_>, options: &ChainParseOptions, ) -> Result<Self>

Parse an AttributeChain from a ParseStream with custom options.

§Errors

Returns syn::Error when the token stream is not a supported path or dot-call chain, completion probes are disabled for probe syntax, or the configured completion marker cannot be emitted as a Rust identifier.

Source

pub fn parse_tokens_with_options( tokens: TokenStream, options: &ChainParseOptions, ) -> Result<Self>

Parse an AttributeChain from tokens with custom options.

§Errors

Returns syn::Error for the same syntax and option failures as Self::parse_with_options.

Source

pub fn root(&self) -> &Path

Source

pub fn root_path(&self) -> &Path

Examples found in repository ?

examples/derive_field_attrs.rs (line 68)

55fn expand_field_attrs(field: &Field) -> syn::Result<Vec<TokenStream>> {
56    let field_ident = field
57        .ident
58        .as_ref()
59        .expect("named_fields only returns named struct fields");
60    let mut expansions = Vec::new();
61
62    for attr in &field.attrs {
63        if !attr.path().is_ident("attribute_dsl") {
64            continue;
65        }
66
67        let chain = attr.parse_args::<AttributeChain>()?;
68        let root = substitute_infer_in_path(chain.root_path(), &field.ty);
69
70        let calls = chain.calls().iter().map(|call| {
71            let method = call.method();
72            let turbofish = call.turbofish();
73            let args = call.args();
74            quote! { .#method #turbofish (#(#args),*) }
75        });
76
77        let completion = chain
78            .completion_marker()
79            .map(|marker| quote! { .#marker })
80            .unwrap_or_default();
81
82        expansions.push(quote! {
83            let _ = #root::builder_for(stringify!(#field_ident)) #(#calls)* #completion;
84        });
85    }
86
87    Ok(expansions)
88}

Source

pub fn calls(&self) -> &[ChainCall]

Examples found in repository ?

examples/derive_field_attrs.rs (line 70)

55fn expand_field_attrs(field: &Field) -> syn::Result<Vec<TokenStream>> {
56    let field_ident = field
57        .ident
58        .as_ref()
59        .expect("named_fields only returns named struct fields");
60    let mut expansions = Vec::new();
61
62    for attr in &field.attrs {
63        if !attr.path().is_ident("attribute_dsl") {
64            continue;
65        }
66
67        let chain = attr.parse_args::<AttributeChain>()?;
68        let root = substitute_infer_in_path(chain.root_path(), &field.ty);
69
70        let calls = chain.calls().iter().map(|call| {
71            let method = call.method();
72            let turbofish = call.turbofish();
73            let args = call.args();
74            quote! { .#method #turbofish (#(#args),*) }
75        });
76
77        let completion = chain
78            .completion_marker()
79            .map(|marker| quote! { .#marker })
80            .unwrap_or_default();
81
82        expansions.push(quote! {
83            let _ = #root::builder_for(stringify!(#field_ident)) #(#calls)* #completion;
84        });
85    }
86
87    Ok(expansions)
88}

Source

pub fn completion(&self) -> &ChainCompletion

Source

pub fn has_completion_probe(&self) -> bool

Source

pub fn completion_marker(&self) -> Option<&Ident>

Examples found in repository ?

examples/derive_field_attrs.rs (line 78)

55fn expand_field_attrs(field: &Field) -> syn::Result<Vec<TokenStream>> {
56    let field_ident = field
57        .ident
58        .as_ref()
59        .expect("named_fields only returns named struct fields");
60    let mut expansions = Vec::new();
61
62    for attr in &field.attrs {
63        if !attr.path().is_ident("attribute_dsl") {
64            continue;
65        }
66
67        let chain = attr.parse_args::<AttributeChain>()?;
68        let root = substitute_infer_in_path(chain.root_path(), &field.ty);
69
70        let calls = chain.calls().iter().map(|call| {
71            let method = call.method();
72            let turbofish = call.turbofish();
73            let args = call.args();
74            quote! { .#method #turbofish (#(#args),*) }
75        });
76
77        let completion = chain
78            .completion_marker()
79            .map(|marker| quote! { .#marker })
80            .unwrap_or_default();
81
82        expansions.push(quote! {
83            let _ = #root::builder_for(stringify!(#field_ident)) #(#calls)* #completion;
84        });
85    }
86
87    Ok(expansions)
88}