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| <span id="660">660</span> |
| <span id="661">661</span> |
| <span id="662">662</span> |
| </pre><pre class="rust"><code><span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::punctuated::Punctuated</span>; |
| <span class="kw">use</span> <span class="ident">proc_macro2::TokenStream</span>; |
| <span class="kw">use</span> <span class="ident">std::iter</span>; |
| <span class="kw">use</span> <span class="ident">std::slice</span>; |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::parse</span>::{<span class="ident">Parse</span>, <span class="ident">ParseBuffer</span>, <span class="ident">ParseStream</span>, <span class="ident">Parser</span>, <span class="prelude-ty">Result</span>}; |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::punctuated::Pair</span>; |
| |
| <span class="macro">ast_struct!</span> { |
| <span class="doccomment">/// An attribute like `#[repr(transparent)]`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This type is available only if Syn is built with the `"derive"` or `"full"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// <br></span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Syntax</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Rust has six types of attributes.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// - Outer attributes like `#[repr(transparent)]`. These appear outside or</span> |
| <span class="doccomment">/// in front of the item they describe.</span> |
| <span class="doccomment">/// - Inner attributes like `#![feature(proc_macro)]`. These appear inside</span> |
| <span class="doccomment">/// of the item they describe, usually a module.</span> |
| <span class="doccomment">/// - Outer doc comments like `/// # Example`.</span> |
| <span class="doccomment">/// - Inner doc comments like `//! Please file an issue`.</span> |
| <span class="doccomment">/// - Outer block comments `/** # Example */`.</span> |
| <span class="doccomment">/// - Inner block comments `/*! Please file an issue */`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The `style` field of type `AttrStyle` distinguishes whether an attribute</span> |
| <span class="doccomment">/// is outer or inner. Doc comments and block comments are promoted to</span> |
| <span class="doccomment">/// attributes, as this is how they are processed by the compiler and by</span> |
| <span class="doccomment">/// `macro_rules!` macros.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The `path` field gives the possibly colon-delimited path against which</span> |
| <span class="doccomment">/// the attribute is resolved. It is equal to `"doc"` for desugared doc</span> |
| <span class="doccomment">/// comments. The `tokens` field contains the rest of the attribute body as</span> |
| <span class="doccomment">/// tokens.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```text</span> |
| <span class="doccomment">/// #[derive(Copy)] #[crate::precondition x < 5]</span> |
| <span class="doccomment">/// ^^^^^^~~~~~~ ^^^^^^^^^^^^^^^^^^^ ~~~~~</span> |
| <span class="doccomment">/// path tokens path tokens</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// <br></span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Parsing from tokens to Attribute</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This type does not implement the [`Parse`] trait and thus cannot be</span> |
| <span class="doccomment">/// parsed directly by [`ParseStream::parse`]. Instead use</span> |
| <span class="doccomment">/// [`ParseStream::call`] with one of the two parser functions</span> |
| <span class="doccomment">/// [`Attribute::parse_outer`] or [`Attribute::parse_inner`] depending on</span> |
| <span class="doccomment">/// which you intend to parse.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// [`Parse`]: parse::Parse</span> |
| <span class="doccomment">/// [`ParseStream::parse`]: parse::ParseBuffer::parse</span> |
| <span class="doccomment">/// [`ParseStream::call`]: parse::ParseBuffer::call</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">/// use syn::{Attribute, Ident, Result, Token};</span> |
| <span class="doccomment">/// use syn::parse::{Parse, ParseStream};</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// // Parses a unit struct with attributes.</span> |
| <span class="doccomment">/// //</span> |
| <span class="doccomment">/// // #[path = "s.tmpl"]</span> |
| <span class="doccomment">/// // struct S;</span> |
| <span class="doccomment">/// struct UnitStruct {</span> |
| <span class="doccomment">/// attrs: Vec<Attribute>,</span> |
| <span class="doccomment">/// struct_token: Token![struct],</span> |
| <span class="doccomment">/// name: Ident,</span> |
| <span class="doccomment">/// semi_token: Token![;],</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// impl Parse for UnitStruct {</span> |
| <span class="doccomment">/// fn parse(input: ParseStream) -> Result<Self> {</span> |
| <span class="doccomment">/// Ok(UnitStruct {</span> |
| <span class="doccomment">/// attrs: input.call(Attribute::parse_outer)?,</span> |
| <span class="doccomment">/// struct_token: input.parse()?,</span> |
| <span class="doccomment">/// name: input.parse()?,</span> |
| <span class="doccomment">/// semi_token: input.parse()?,</span> |
| <span class="doccomment">/// })</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// <p><br></p></span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Parsing from Attribute to structured arguments</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The grammar of attributes in Rust is very flexible, which makes the</span> |
| <span class="doccomment">/// syntax tree not that useful on its own. In particular, arguments of the</span> |
| <span class="doccomment">/// attribute are held in an arbitrary `tokens: TokenStream`. Macros are</span> |
| <span class="doccomment">/// expected to check the `path` of the attribute, decide whether they</span> |
| <span class="doccomment">/// recognize it, and then parse the remaining tokens according to whatever</span> |
| <span class="doccomment">/// grammar they wish to require for that kind of attribute.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// If the attribute you are parsing is expected to conform to the</span> |
| <span class="doccomment">/// conventional structured form of attribute, use [`parse_meta()`] to</span> |
| <span class="doccomment">/// obtain that structured representation. If the attribute follows some</span> |
| <span class="doccomment">/// other grammar of its own, use [`parse_args()`] to parse that into the</span> |
| <span class="doccomment">/// expected data structure.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// [`parse_meta()`]: Attribute::parse_meta</span> |
| <span class="doccomment">/// [`parse_args()`]: Attribute::parse_args</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// <p><br></p></span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Doc comments</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The compiler transforms doc comments, such as `/// comment` and `/*!</span> |
| <span class="doccomment">/// comment */`, into attributes before macros are expanded. Each comment is</span> |
| <span class="doccomment">/// expanded into an attribute of the form `#[doc = r"comment"]`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// As an example, the following `mod` items are expanded identically:</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">/// # use syn::{ItemMod, parse_quote};</span> |
| <span class="doccomment">/// let doc: ItemMod = parse_quote! {</span> |
| <span class="doccomment">/// /// Single line doc comments</span> |
| <span class="doccomment">/// /// We write so many!</span> |
| <span class="doccomment">/// /**</span> |
| <span class="doccomment">/// * Multi-line comments...</span> |
| <span class="doccomment">/// * May span many lines</span> |
| <span class="doccomment">/// */</span> |
| <span class="doccomment">/// mod example {</span> |
| <span class="doccomment">/// //! Of course, they can be inner too</span> |
| <span class="doccomment">/// /*! And fit in a single line */</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">/// };</span> |
| <span class="doccomment">/// let attr: ItemMod = parse_quote! {</span> |
| <span class="doccomment">/// #[doc = r" Single line doc comments"]</span> |
| <span class="doccomment">/// #[doc = r" We write so many!"]</span> |
| <span class="doccomment">/// #[doc = r"</span> |
| <span class="doccomment">/// * Multi-line comments...</span> |
| <span class="doccomment">/// * May span many lines</span> |
| <span class="doccomment">/// "]</span> |
| <span class="doccomment">/// mod example {</span> |
| <span class="doccomment">/// #![doc = r" Of course, they can be inner too"]</span> |
| <span class="doccomment">/// #![doc = r" And fit in a single line "]</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">/// };</span> |
| <span class="doccomment">/// assert_eq!(doc, attr);</span> |
| <span class="doccomment">/// ```</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Attribute</span> { |
| <span class="kw">pub</span> <span class="ident">pound_token</span>: <span class="macro">Token!</span>[#], |
| <span class="kw">pub</span> <span class="ident">style</span>: <span class="ident">AttrStyle</span>, |
| <span class="kw">pub</span> <span class="ident">bracket_token</span>: <span class="ident">token::Bracket</span>, |
| <span class="kw">pub</span> <span class="ident">path</span>: <span class="ident">Path</span>, |
| <span class="kw">pub</span> <span class="ident">tokens</span>: <span class="ident">TokenStream</span>, |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">Attribute</span> { |
| <span class="doccomment">/// Parses the content of the attribute, consisting of the path and tokens,</span> |
| <span class="doccomment">/// as a [`Meta`] if possible.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This function is available only if Syn is built with the `"parsing"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_meta</span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Meta</span><span class="op">></span> { |
| <span class="kw">fn</span> <span class="ident">clone_ident_segment</span>(<span class="ident">segment</span>: <span class="kw-2">&</span><span class="ident">PathSegment</span>) -> <span class="ident">PathSegment</span> { |
| <span class="ident">PathSegment</span> { |
| <span class="ident">ident</span>: <span class="ident">segment</span>.<span class="ident">ident</span>.<span class="ident">clone</span>(), |
| <span class="ident">arguments</span>: <span class="ident">PathArguments::None</span>, |
| } |
| } |
| |
| <span class="kw">let</span> <span class="ident">path</span> <span class="op">=</span> <span class="ident">Path</span> { |
| <span class="ident">leading_colon</span>: <span class="self">self</span> |
| .<span class="ident">path</span> |
| .<span class="ident">leading_colon</span> |
| .<span class="ident">as_ref</span>() |
| .<span class="ident">map</span>(<span class="op">|</span><span class="ident">colon</span><span class="op">|</span> <span class="macro">Token!</span>[::](<span class="ident">colon</span>.<span class="ident">spans</span>)), |
| <span class="ident">segments</span>: <span class="self">self</span> |
| .<span class="ident">path</span> |
| .<span class="ident">segments</span> |
| .<span class="ident">pairs</span>() |
| .<span class="ident">map</span>(<span class="op">|</span><span class="ident">pair</span><span class="op">|</span> <span class="kw">match</span> <span class="ident">pair</span> { |
| <span class="ident">Pair::Punctuated</span>(<span class="ident">seg</span>, <span class="ident">punct</span>) => { |
| <span class="ident">Pair::Punctuated</span>(<span class="ident">clone_ident_segment</span>(<span class="ident">seg</span>), <span class="macro">Token!</span>[::](<span class="ident">punct</span>.<span class="ident">spans</span>)) |
| } |
| <span class="ident">Pair::End</span>(<span class="ident">seg</span>) => <span class="ident">Pair::End</span>(<span class="ident">clone_ident_segment</span>(<span class="ident">seg</span>)), |
| }) |
| .<span class="ident">collect</span>(), |
| }; |
| |
| <span class="kw">let</span> <span class="ident">parser</span> <span class="op">=</span> <span class="op">|</span><span class="ident">input</span>: <span class="ident">ParseStream</span><span class="op">|</span> <span class="ident">parsing::parse_meta_after_path</span>(<span class="ident">path</span>, <span class="ident">input</span>); |
| <span class="ident">parse::Parser::parse2</span>(<span class="ident">parser</span>, <span class="self">self</span>.<span class="ident">tokens</span>.<span class="ident">clone</span>()) |
| } |
| |
| <span class="doccomment">/// Parse the arguments to the attribute as a syntax tree.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This is similar to `syn::parse2::<T>(attr.tokens)` except that:</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// - the surrounding delimiters are *not* included in the input to the</span> |
| <span class="doccomment">/// parser; and</span> |
| <span class="doccomment">/// - the error message has a more useful span when `tokens` is empty.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```text</span> |
| <span class="doccomment">/// #[my_attr(value < 5)]</span> |
| <span class="doccomment">/// ^^^^^^^^^ what gets parsed</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This function is available only if Syn is built with the `"parsing"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_args</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Parse</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> { |
| <span class="self">self</span>.<span class="ident">parse_args_with</span>(<span class="ident">T::parse</span>) |
| } |
| |
| <span class="doccomment">/// Parse the arguments to the attribute using the given parser.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This function is available only if Syn is built with the `"parsing"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_args_with</span><span class="op"><</span><span class="ident">F</span>: <span class="ident">Parser</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">parser</span>: <span class="ident">F</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">F::Output</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">parser</span> <span class="op">=</span> <span class="op">|</span><span class="ident">input</span>: <span class="ident">ParseStream</span><span class="op">|</span> { |
| <span class="kw">let</span> <span class="ident">args</span> <span class="op">=</span> <span class="ident">enter_args</span>(<span class="self">self</span>, <span class="ident">input</span>)<span class="question-mark">?</span>; |
| <span class="ident">parse::parse_stream</span>(<span class="ident">parser</span>, <span class="kw-2">&</span><span class="ident">args</span>) |
| }; |
| <span class="ident">parser</span>.<span class="ident">parse2</span>(<span class="self">self</span>.<span class="ident">tokens</span>.<span class="ident">clone</span>()) |
| } |
| |
| <span class="doccomment">/// Parses zero or more outer attributes from the stream.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This function is available only if Syn is built with the `"parsing"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_outer</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="self">Self</span><span class="op">></span><span class="op">></span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">attrs</span> <span class="op">=</span> <span class="ident">Vec::new</span>(); |
| <span class="kw">while</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="macro">Token!</span>[#]) { |
| <span class="ident">attrs</span>.<span class="ident">push</span>(<span class="ident">input</span>.<span class="ident">call</span>(<span class="ident">parsing::single_parse_outer</span>)<span class="question-mark">?</span>); |
| } |
| <span class="prelude-val">Ok</span>(<span class="ident">attrs</span>) |
| } |
| |
| <span class="doccomment">/// Parses zero or more inner attributes from the stream.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This function is available only if Syn is built with the `"parsing"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_inner</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="self">Self</span><span class="op">></span><span class="op">></span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">attrs</span> <span class="op">=</span> <span class="ident">Vec::new</span>(); |
| <span class="ident">parsing::parse_inner</span>(<span class="ident">input</span>, <span class="kw-2">&mut</span> <span class="ident">attrs</span>)<span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(<span class="ident">attrs</span>) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="kw">fn</span> <span class="ident">expected_parentheses</span>(<span class="ident">attr</span>: <span class="kw-2">&</span><span class="ident">Attribute</span>) -> <span class="ident">String</span> { |
| <span class="kw">let</span> <span class="ident">style</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">attr</span>.<span class="ident">style</span> { |
| <span class="ident">AttrStyle::Outer</span> => <span class="string">"#"</span>, |
| <span class="ident">AttrStyle::Inner</span>(<span class="kw">_</span>) => <span class="string">"#!"</span>, |
| }; |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">path</span> <span class="op">=</span> <span class="ident">String::new</span>(); |
| <span class="kw">for</span> <span class="ident">segment</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">attr</span>.<span class="ident">path</span>.<span class="ident">segments</span> { |
| <span class="kw">if</span> <span class="op">!</span><span class="ident">path</span>.<span class="ident">is_empty</span>() <span class="op">|</span><span class="op">|</span> <span class="ident">attr</span>.<span class="ident">path</span>.<span class="ident">leading_colon</span>.<span class="ident">is_some</span>() { |
| <span class="ident">path</span> <span class="op">+</span><span class="op">=</span> <span class="string">"::"</span>; |
| } |
| <span class="ident">path</span> <span class="op">+</span><span class="op">=</span> <span class="kw-2">&</span><span class="ident">segment</span>.<span class="ident">ident</span>.<span class="ident">to_string</span>(); |
| } |
| |
| <span class="macro">format!</span>(<span class="string">"{}[{}(...)]"</span>, <span class="ident">style</span>, <span class="ident">path</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="kw">fn</span> <span class="ident">enter_args</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>(<span class="ident">attr</span>: <span class="kw-2">&</span><span class="ident">Attribute</span>, <span class="ident">input</span>: <span class="ident">ParseStream</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">ParseBuffer</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span><span class="op">></span> { |
| <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">is_empty</span>() { |
| <span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> <span class="ident">expected_parentheses</span>(<span class="ident">attr</span>); |
| <span class="kw">let</span> <span class="ident">msg</span> <span class="op">=</span> <span class="macro">format!</span>(<span class="string">"expected attribute arguments in parentheses: {}"</span>, <span class="ident">expected</span>); |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident"><span class="kw">crate</span>::error::new2</span>( |
| <span class="ident">attr</span>.<span class="ident">pound_token</span>.<span class="ident">span</span>, |
| <span class="ident">attr</span>.<span class="ident">bracket_token</span>.<span class="ident">span</span>, |
| <span class="ident">msg</span>, |
| )); |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="macro">Token!</span>[<span class="op">=</span>]) { |
| <span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> <span class="ident">expected_parentheses</span>(<span class="ident">attr</span>); |
| <span class="kw">let</span> <span class="ident">msg</span> <span class="op">=</span> <span class="macro">format!</span>(<span class="string">"expected parentheses: {}"</span>, <span class="ident">expected</span>); |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">input</span>.<span class="ident">error</span>(<span class="ident">msg</span>)); |
| }; |
| |
| <span class="kw">let</span> <span class="ident">content</span>; |
| <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">token::Paren</span>) { |
| <span class="macro">parenthesized!</span>(<span class="ident">content</span> <span class="kw">in</span> <span class="ident">input</span>); |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">token::Bracket</span>) { |
| <span class="macro">bracketed!</span>(<span class="ident">content</span> <span class="kw">in</span> <span class="ident">input</span>); |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">token::Brace</span>) { |
| <span class="macro">braced!</span>(<span class="ident">content</span> <span class="kw">in</span> <span class="ident">input</span>); |
| } <span class="kw">else</span> { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">input</span>.<span class="ident">error</span>(<span class="string">"unexpected token in attribute arguments"</span>)); |
| } |
| |
| <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">is_empty</span>() { |
| <span class="prelude-val">Ok</span>(<span class="ident">content</span>) |
| } <span class="kw">else</span> { |
| <span class="prelude-val">Err</span>(<span class="ident">input</span>.<span class="ident">error</span>(<span class="string">"unexpected token in attribute arguments"</span>)) |
| } |
| } |
| |
| <span class="macro">ast_enum!</span> { |
| <span class="doccomment">/// Distinguishes between attributes that decorate an item and attributes</span> |
| <span class="doccomment">/// that are contained within an item.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This type is available only if Syn is built with the `"derive"` or `"full"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Outer attributes</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// - `#[repr(transparent)]`</span> |
| <span class="doccomment">/// - `/// # Example`</span> |
| <span class="doccomment">/// - `/** Please file an issue */`</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Inner attributes</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// - `#![feature(proc_macro)]`</span> |
| <span class="doccomment">/// - `//! # Example`</span> |
| <span class="doccomment">/// - `/*! Please file an issue */`</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">AttrStyle</span> { |
| <span class="ident">Outer</span>, |
| <span class="ident">Inner</span>(<span class="macro">Token!</span>[<span class="op">!</span>]), |
| } |
| } |
| |
| <span class="macro">ast_enum_of_structs!</span> { |
| <span class="doccomment">/// Content of a compile-time structured attribute.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This type is available only if Syn is built with the `"derive"` or `"full"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ## Path</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// A meta path is like the `test` in `#[test]`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ## List</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// A meta list is like the `derive(Copy)` in `#[derive(Copy)]`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ## NameValue</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// A name-value meta is like the `path = "..."` in `#[path =</span> |
| <span class="doccomment">/// "sys/windows.rs"]`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Syntax tree enum</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This type is a [syntax tree enum].</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// [syntax tree enum]: Expr#syntax-tree-enums</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">Meta</span> { |
| <span class="ident">Path</span>(<span class="ident">Path</span>), |
| |
| <span class="doccomment">/// A structured list within an attribute, like `derive(Copy, Clone)`.</span> |
| <span class="ident">List</span>(<span class="ident">MetaList</span>), |
| |
| <span class="doccomment">/// A name-value pair within an attribute, like `feature = "nightly"`.</span> |
| <span class="ident">NameValue</span>(<span class="ident">MetaNameValue</span>), |
| } |
| } |
| |
| <span class="macro">ast_struct!</span> { |
| <span class="doccomment">/// A structured list within an attribute, like `derive(Copy, Clone)`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This type is available only if Syn is built with the `"derive"` or</span> |
| <span class="doccomment">/// `"full"` feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">MetaList</span> { |
| <span class="kw">pub</span> <span class="ident">path</span>: <span class="ident">Path</span>, |
| <span class="kw">pub</span> <span class="ident">paren_token</span>: <span class="ident">token::Paren</span>, |
| <span class="kw">pub</span> <span class="ident">nested</span>: <span class="ident">Punctuated</span><span class="op"><</span><span class="ident">NestedMeta</span>, <span class="macro">Token!</span>[,]<span class="op">></span>, |
| } |
| } |
| |
| <span class="macro">ast_struct!</span> { |
| <span class="doccomment">/// A name-value pair within an attribute, like `feature = "nightly"`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This type is available only if Syn is built with the `"derive"` or</span> |
| <span class="doccomment">/// `"full"` feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">MetaNameValue</span> { |
| <span class="kw">pub</span> <span class="ident">path</span>: <span class="ident">Path</span>, |
| <span class="kw">pub</span> <span class="ident">eq_token</span>: <span class="macro">Token!</span>[<span class="op">=</span>], |
| <span class="kw">pub</span> <span class="ident">lit</span>: <span class="ident">Lit</span>, |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">Meta</span> { |
| <span class="doccomment">/// Returns the identifier that begins this structured meta item.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// For example this would return the `test` in `#[test]`, the `derive` in</span> |
| <span class="doccomment">/// `#[derive(Copy)]`, and the `path` in `#[path = "sys/windows.rs"]`.</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">path</span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="ident">Path</span> { |
| <span class="kw">match</span> <span class="self">self</span> { |
| <span class="ident">Meta::Path</span>(<span class="ident">path</span>) => <span class="ident">path</span>, |
| <span class="ident">Meta::List</span>(<span class="ident">meta</span>) => <span class="kw-2">&</span><span class="ident">meta</span>.<span class="ident">path</span>, |
| <span class="ident">Meta::NameValue</span>(<span class="ident">meta</span>) => <span class="kw-2">&</span><span class="ident">meta</span>.<span class="ident">path</span>, |
| } |
| } |
| } |
| |
| <span class="macro">ast_enum_of_structs!</span> { |
| <span class="doccomment">/// Element of a compile-time attribute list.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// *This type is available only if Syn is built with the `"derive"` or `"full"`</span> |
| <span class="doccomment">/// feature.*</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">NestedMeta</span> { |
| <span class="doccomment">/// A structured meta item, like the `Copy` in `#[derive(Copy)]` which</span> |
| <span class="doccomment">/// would be a nested `Meta::Path`.</span> |
| <span class="ident">Meta</span>(<span class="ident">Meta</span>), |
| |
| <span class="doccomment">/// A Rust literal, like the `"new_name"` in `#[rename("new_name")]`.</span> |
| <span class="ident">Lit</span>(<span class="ident">Lit</span>), |
| } |
| } |
| |
| <span class="doccomment">/// Conventional argument type associated with an invocation of an attribute</span> |
| <span class="doccomment">/// macro.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// For example if we are developing an attribute macro that is intended to be</span> |
| <span class="doccomment">/// invoked on function items as follows:</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">/// # const IGNORE: &str = stringify! {</span> |
| <span class="doccomment">/// #[my_attribute(path = "/v1/refresh")]</span> |
| <span class="doccomment">/// # };</span> |
| <span class="doccomment">/// pub fn refresh() {</span> |
| <span class="doccomment">/// /* ... */</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The implementation of this macro would want to parse its attribute arguments</span> |
| <span class="doccomment">/// as type `AttributeArgs`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">/// # extern crate proc_macro;</span> |
| <span class="doccomment">/// #</span> |
| <span class="doccomment">/// use proc_macro::TokenStream;</span> |
| <span class="doccomment">/// use syn::{parse_macro_input, AttributeArgs, ItemFn};</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # const IGNORE: &str = stringify! {</span> |
| <span class="doccomment">/// #[proc_macro_attribute]</span> |
| <span class="doccomment">/// # };</span> |
| <span class="doccomment">/// pub fn my_attribute(args: TokenStream, input: TokenStream) -> TokenStream {</span> |
| <span class="doccomment">/// let args = parse_macro_input!(args as AttributeArgs);</span> |
| <span class="doccomment">/// let input = parse_macro_input!(input as ItemFn);</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// /* ... */</span> |
| <span class="doccomment">/// # "".parse().unwrap()</span> |
| <span class="doccomment">/// }</span> |
| <span class="doccomment">/// ```</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"full"</span>, <span class="ident">feature</span> <span class="op">=</span> <span class="string">"derive"</span>))))]</span> |
| <span class="kw">pub</span> <span class="kw">type</span> <span class="ident">AttributeArgs</span> <span class="op">=</span> <span class="ident">Vec</span><span class="op"><</span><span class="ident">NestedMeta</span><span class="op">></span>; |
| |
| <span class="kw">pub</span> <span class="kw">trait</span> <span class="ident">FilterAttrs</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { |
| <span class="kw">type</span> <span class="ident">Ret</span>: <span class="ident">Iterator</span><span class="op"><</span><span class="ident">Item</span> <span class="op">=</span> <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">Attribute</span><span class="op">></span>; |
| |
| <span class="kw">fn</span> <span class="ident">outer</span>(<span class="self">self</span>) -> <span class="ident"><span class="self">Self</span>::Ret</span>; |
| <span class="kw">fn</span> <span class="ident">inner</span>(<span class="self">self</span>) -> <span class="ident"><span class="self">Self</span>::Ret</span>; |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">FilterAttrs</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="kw-2">&</span><span class="lifetime">'a</span> [<span class="ident">Attribute</span>] { |
| <span class="kw">type</span> <span class="ident">Ret</span> <span class="op">=</span> <span class="ident">iter::Filter</span><span class="op"><</span><span class="ident">slice::Iter</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">Attribute</span><span class="op">></span>, <span class="kw">fn</span>(<span class="op">&&</span><span class="ident">Attribute</span>) -> <span class="ident">bool</span><span class="op">></span>; |
| |
| <span class="kw">fn</span> <span class="ident">outer</span>(<span class="self">self</span>) -> <span class="ident"><span class="self">Self</span>::Ret</span> { |
| <span class="kw">fn</span> <span class="ident">is_outer</span>(<span class="ident">attr</span>: <span class="op">&&</span><span class="ident">Attribute</span>) -> <span class="ident">bool</span> { |
| <span class="kw">match</span> <span class="ident">attr</span>.<span class="ident">style</span> { |
| <span class="ident">AttrStyle::Outer</span> => <span class="bool-val">true</span>, |
| <span class="ident">AttrStyle::Inner</span>(<span class="kw">_</span>) => <span class="bool-val">false</span>, |
| } |
| } |
| <span class="self">self</span>.<span class="ident">iter</span>().<span class="ident">filter</span>(<span class="ident">is_outer</span>) |
| } |
| |
| <span class="kw">fn</span> <span class="ident">inner</span>(<span class="self">self</span>) -> <span class="ident"><span class="self">Self</span>::Ret</span> { |
| <span class="kw">fn</span> <span class="ident">is_inner</span>(<span class="ident">attr</span>: <span class="op">&&</span><span class="ident">Attribute</span>) -> <span class="ident">bool</span> { |
| <span class="kw">match</span> <span class="ident">attr</span>.<span class="ident">style</span> { |
| <span class="ident">AttrStyle::Inner</span>(<span class="kw">_</span>) => <span class="bool-val">true</span>, |
| <span class="ident">AttrStyle::Outer</span> => <span class="bool-val">false</span>, |
| } |
| } |
| <span class="self">self</span>.<span class="ident">iter</span>().<span class="ident">filter</span>(<span class="ident">is_inner</span>) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">mod</span> <span class="ident">parsing</span> { |
| <span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::ext::IdentExt</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::parse</span>::{<span class="ident">Parse</span>, <span class="ident">ParseStream</span>, <span class="prelude-ty">Result</span>}; |
| |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_inner</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>, <span class="ident">attrs</span>: <span class="kw-2">&mut</span> <span class="ident">Vec</span><span class="op"><</span><span class="ident">Attribute</span><span class="op">></span>) -> <span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { |
| <span class="kw">while</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="macro">Token!</span>[#]) <span class="op">&&</span> <span class="ident">input</span>.<span class="ident">peek2</span>(<span class="macro">Token!</span>[<span class="op">!</span>]) { |
| <span class="ident">attrs</span>.<span class="ident">push</span>(<span class="ident">input</span>.<span class="ident">call</span>(<span class="ident">parsing::single_parse_inner</span>)<span class="question-mark">?</span>); |
| } |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">single_parse_inner</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Attribute</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">content</span>; |
| <span class="prelude-val">Ok</span>(<span class="ident">Attribute</span> { |
| <span class="ident">pound_token</span>: <span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| <span class="ident">style</span>: <span class="ident">AttrStyle::Inner</span>(<span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>), |
| <span class="ident">bracket_token</span>: <span class="macro">bracketed!</span>(<span class="ident">content</span> <span class="kw">in</span> <span class="ident">input</span>), |
| <span class="ident">path</span>: <span class="ident">content</span>.<span class="ident">call</span>(<span class="ident">Path::parse_mod_style</span>)<span class="question-mark">?</span>, |
| <span class="ident">tokens</span>: <span class="ident">content</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| }) |
| } |
| |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">single_parse_outer</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Attribute</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">content</span>; |
| <span class="prelude-val">Ok</span>(<span class="ident">Attribute</span> { |
| <span class="ident">pound_token</span>: <span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| <span class="ident">style</span>: <span class="ident">AttrStyle::Outer</span>, |
| <span class="ident">bracket_token</span>: <span class="macro">bracketed!</span>(<span class="ident">content</span> <span class="kw">in</span> <span class="ident">input</span>), |
| <span class="ident">path</span>: <span class="ident">content</span>.<span class="ident">call</span>(<span class="ident">Path::parse_mod_style</span>)<span class="question-mark">?</span>, |
| <span class="ident">tokens</span>: <span class="ident">content</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| }) |
| } |
| |
| <span class="comment">// Like Path::parse_mod_style but accepts keywords in the path.</span> |
| <span class="kw">fn</span> <span class="ident">parse_meta_path</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Path</span><span class="op">></span> { |
| <span class="prelude-val">Ok</span>(<span class="ident">Path</span> { |
| <span class="ident">leading_colon</span>: <span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| <span class="ident">segments</span>: { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">segments</span> <span class="op">=</span> <span class="ident">Punctuated::new</span>(); |
| <span class="kw">while</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">Ident::peek_any</span>) { |
| <span class="kw">let</span> <span class="ident">ident</span> <span class="op">=</span> <span class="ident">Ident::parse_any</span>(<span class="ident">input</span>)<span class="question-mark">?</span>; |
| <span class="ident">segments</span>.<span class="ident">push_value</span>(<span class="ident">PathSegment::from</span>(<span class="ident">ident</span>)); |
| <span class="kw">if</span> <span class="op">!</span><span class="ident">input</span>.<span class="ident">peek</span>(<span class="macro">Token!</span>[::]) { |
| <span class="kw">break</span>; |
| } |
| <span class="kw">let</span> <span class="ident">punct</span> <span class="op">=</span> <span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>; |
| <span class="ident">segments</span>.<span class="ident">push_punct</span>(<span class="ident">punct</span>); |
| } |
| <span class="kw">if</span> <span class="ident">segments</span>.<span class="ident">is_empty</span>() { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">input</span>.<span class="ident">error</span>(<span class="string">"expected path"</span>)); |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">segments</span>.<span class="ident">trailing_punct</span>() { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">input</span>.<span class="ident">error</span>(<span class="string">"expected path segment"</span>)); |
| } |
| <span class="ident">segments</span> |
| }, |
| }) |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">Parse</span> <span class="kw">for</span> <span class="ident">Meta</span> { |
| <span class="kw">fn</span> <span class="ident">parse</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="self">Self</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">path</span> <span class="op">=</span> <span class="ident">input</span>.<span class="ident">call</span>(<span class="ident">parse_meta_path</span>)<span class="question-mark">?</span>; |
| <span class="ident">parse_meta_after_path</span>(<span class="ident">path</span>, <span class="ident">input</span>) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">Parse</span> <span class="kw">for</span> <span class="ident">MetaList</span> { |
| <span class="kw">fn</span> <span class="ident">parse</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="self">Self</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">path</span> <span class="op">=</span> <span class="ident">input</span>.<span class="ident">call</span>(<span class="ident">parse_meta_path</span>)<span class="question-mark">?</span>; |
| <span class="ident">parse_meta_list_after_path</span>(<span class="ident">path</span>, <span class="ident">input</span>) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">Parse</span> <span class="kw">for</span> <span class="ident">MetaNameValue</span> { |
| <span class="kw">fn</span> <span class="ident">parse</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="self">Self</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">path</span> <span class="op">=</span> <span class="ident">input</span>.<span class="ident">call</span>(<span class="ident">parse_meta_path</span>)<span class="question-mark">?</span>; |
| <span class="ident">parse_meta_name_value_after_path</span>(<span class="ident">path</span>, <span class="ident">input</span>) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"parsing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">Parse</span> <span class="kw">for</span> <span class="ident">NestedMeta</span> { |
| <span class="kw">fn</span> <span class="ident">parse</span>(<span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="self">Self</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">Lit</span>) <span class="op">&&</span> <span class="op">!</span>(<span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">LitBool</span>) <span class="op">&&</span> <span class="ident">input</span>.<span class="ident">peek2</span>(<span class="macro">Token!</span>[<span class="op">=</span>])) { |
| <span class="ident">input</span>.<span class="ident">parse</span>().<span class="ident">map</span>(<span class="ident">NestedMeta::Lit</span>) |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">Ident::peek_any</span>) |
| <span class="op">|</span><span class="op">|</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="macro">Token!</span>[::]) <span class="op">&&</span> <span class="ident">input</span>.<span class="ident">peek3</span>(<span class="ident">Ident::peek_any</span>) |
| { |
| <span class="ident">input</span>.<span class="ident">parse</span>().<span class="ident">map</span>(<span class="ident">NestedMeta::Meta</span>) |
| } <span class="kw">else</span> { |
| <span class="prelude-val">Err</span>(<span class="ident">input</span>.<span class="ident">error</span>(<span class="string">"expected identifier or literal"</span>)) |
| } |
| } |
| } |
| |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">parse_meta_after_path</span>(<span class="ident">path</span>: <span class="ident">Path</span>, <span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Meta</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="ident">token::Paren</span>) { |
| <span class="ident">parse_meta_list_after_path</span>(<span class="ident">path</span>, <span class="ident">input</span>).<span class="ident">map</span>(<span class="ident">Meta::List</span>) |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">input</span>.<span class="ident">peek</span>(<span class="macro">Token!</span>[<span class="op">=</span>]) { |
| <span class="ident">parse_meta_name_value_after_path</span>(<span class="ident">path</span>, <span class="ident">input</span>).<span class="ident">map</span>(<span class="ident">Meta::NameValue</span>) |
| } <span class="kw">else</span> { |
| <span class="prelude-val">Ok</span>(<span class="ident">Meta::Path</span>(<span class="ident">path</span>)) |
| } |
| } |
| |
| <span class="kw">fn</span> <span class="ident">parse_meta_list_after_path</span>(<span class="ident">path</span>: <span class="ident">Path</span>, <span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">MetaList</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">content</span>; |
| <span class="prelude-val">Ok</span>(<span class="ident">MetaList</span> { |
| <span class="ident">path</span>, |
| <span class="ident">paren_token</span>: <span class="macro">parenthesized!</span>(<span class="ident">content</span> <span class="kw">in</span> <span class="ident">input</span>), |
| <span class="ident">nested</span>: <span class="ident">content</span>.<span class="ident">parse_terminated</span>(<span class="ident">NestedMeta::parse</span>)<span class="question-mark">?</span>, |
| }) |
| } |
| |
| <span class="kw">fn</span> <span class="ident">parse_meta_name_value_after_path</span>(<span class="ident">path</span>: <span class="ident">Path</span>, <span class="ident">input</span>: <span class="ident">ParseStream</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">MetaNameValue</span><span class="op">></span> { |
| <span class="prelude-val">Ok</span>(<span class="ident">MetaNameValue</span> { |
| <span class="ident">path</span>, |
| <span class="ident">eq_token</span>: <span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| <span class="ident">lit</span>: <span class="ident">input</span>.<span class="ident">parse</span>()<span class="question-mark">?</span>, |
| }) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"printing"</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">printing</span> { |
| <span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use</span> <span class="ident">proc_macro2::TokenStream</span>; |
| <span class="kw">use</span> <span class="ident">quote::ToTokens</span>; |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"printing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">ToTokens</span> <span class="kw">for</span> <span class="ident">Attribute</span> { |
| <span class="kw">fn</span> <span class="ident">to_tokens</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">tokens</span>: <span class="kw-2">&mut</span> <span class="ident">TokenStream</span>) { |
| <span class="self">self</span>.<span class="ident">pound_token</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| <span class="kw">if</span> <span class="kw">let</span> <span class="ident">AttrStyle::Inner</span>(<span class="ident">b</span>) <span class="op">=</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">style</span> { |
| <span class="ident">b</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| } |
| <span class="self">self</span>.<span class="ident">bracket_token</span>.<span class="ident">surround</span>(<span class="ident">tokens</span>, <span class="op">|</span><span class="ident">tokens</span><span class="op">|</span> { |
| <span class="self">self</span>.<span class="ident">path</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| <span class="self">self</span>.<span class="ident">tokens</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| }); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"printing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">ToTokens</span> <span class="kw">for</span> <span class="ident">MetaList</span> { |
| <span class="kw">fn</span> <span class="ident">to_tokens</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">tokens</span>: <span class="kw-2">&mut</span> <span class="ident">TokenStream</span>) { |
| <span class="self">self</span>.<span class="ident">path</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| <span class="self">self</span>.<span class="ident">paren_token</span>.<span class="ident">surround</span>(<span class="ident">tokens</span>, <span class="op">|</span><span class="ident">tokens</span><span class="op">|</span> { |
| <span class="self">self</span>.<span class="ident">nested</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| }); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"printing"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">ToTokens</span> <span class="kw">for</span> <span class="ident">MetaNameValue</span> { |
| <span class="kw">fn</span> <span class="ident">to_tokens</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">tokens</span>: <span class="kw-2">&mut</span> <span class="ident">TokenStream</span>) { |
| <span class="self">self</span>.<span class="ident">path</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| <span class="self">self</span>.<span class="ident">eq_token</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| <span class="self">self</span>.<span class="ident">lit</span>.<span class="ident">to_tokens</span>(<span class="ident">tokens</span>); |
| } |
| } |
| } |
| </code></pre></div> |
| </section><section id="search" class="content hidden"></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="syn" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.60.0-nightly (1bd4fdc94 2022-01-12)" ></div> |
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