ItemFn from the syn crate holds the parsed TokenStream of a Rust function. parse_macro_input! is a helper macro provided by syn. 2.

Library to serialize and deserialize Syn syntax trees. - taiki-e/syn-serde

Foreign function definition (ex. fn foo(x: usize) -> bool ) Parse into Struct syn::ForeignItemFn , which includes a signature. use quote:: quote; use syn:: visit::{self, Visit}; use syn::{File, ItemFn}; struct FnVisitor < 'ast > { functions: Vec < & 'ast ItemFn >, } impl < 'ast > Visit < 'ast > for FnVisitor < 'ast > { fn visit_item_fn (& mut self, node: & 'ast ItemFn) { self. functions.

Using some examples and comments from other issues, I was able to get a broken rough protot The result of that is a syn::Item which is an enum of all the different types of rust Items and will allow us to determine exactly what our attribute is decorating. For us, we only want this to work on functions, so we match parse2 , if it is a fn we pass the inner data off to handle_func if not, we panic with a message about only supporting fn s. 2018-06-12 61,480 downloads per month Used in 40 crates (2 directly). Apache-2.0 OR MIT. 29KB 682 lines.

For us, we only want this to work on functions, so we match parse2 , if it is a fn we pass the inner data off to handle_func if not, we panic with a message about only supporting fn s. I have requirement to get the source location of the caller of every method.

Struct syn:: ItemFn −] pub struct This type is available only if Syn is built with the "full" feature. Fields attrs: Vec vis: Visibility sig

attrs; let vis = & input. vis; let sig = & mut input. sig; let body = & input.

Syn is a parsing library for parsing a stream of Rust tokens into a syntax tree of Rust source code. Currently this library is geared toward use in Rust procedural

I have requirement to get the source location of the caller of every method. I am trying to create a proc_macro_attribute to capture the location and print it. #[proc_macro_attribute] pub fn A pretty common use case (I'd imagine) is the ability to have a macro like the following modify the function body it's defined on.

This type is a syntax tree enum. use syn:: fold:: {self, Fold}; use syn:: parse:: {Parse, ParseStream, Result}; use syn:: punctuated:: Punctuated; use syn:: {parse_macro_input, parse_quote, Expr, Ident, ItemFn, Local, Pat, Stmt, Token}; /// Parses a list of variable names separated by commas.
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Oh, before we go, let's clean one thing up. 2021-02-03 The Syn crate has fairly coarse compile-time control over the set of available syntax tree types. There is default-features = false mode where only the parsing API is provided with no syntax tree types at all, there is features = ["derive"] which is the default and supports structs and enums, and there is features = ["full"] which supports all possible Rust syntax. Teams. Q&A for work.

pub struct ItemFn { pub attrs: Vec < Attribute >, pub vis: Visibility , pub sig: Signature , pub block: Box < Block >, } [ −] Expand description.
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The result of that is a syn::Item which is an enum of all the different types of rust Items and will allow us to determine exactly what our attribute is decorating. For us, we only want this to work on functions, so we match parse2 , if it is a fn we pass the inner data off to handle_func if not, we panic with a message about only supporting fn s.

GitHub Gist: star and fork bstrie's gists by creating an account on GitHub. Trait implementations are provided for primitives, some std types, and some syn types. FromDeriveInput is implemented or derived by each proc-macro crate which depends on darling . This is the root for input parsing; it gets access to the identity, generics, and visibility of the target type, and can specify which attribute names should be parsed or forwarded from the input AST. Syn is a parsing library for parsing a stream of Rust tokens into a syntax tree of Rust source code. Currently this library is geared toward use in Rust procedural macros, but contains some APIs that may be useful more generally. 326,595 downloads per month Used in 1,120 crates (2 directly). MIT license .