├── .gitignore ├── .travis.yml ├── Cargo.toml ├── LICENSE-APACHE ├── LICENSE-MIT ├── README.md └── src ├── invoke_path.rs ├── kv_option.rs ├── lib.rs ├── multiple_val.rs ├── parse_attributes.rs └── parse_ext.rs /.gitignore: -------------------------------------------------------------------------------- 1 | /target 2 | **/*.rs.bk 3 | Cargo.lock 4 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | language: rust 2 | 3 | cache: cargo 4 | 5 | rust: 6 | - stable 7 | - beta 8 | - nightly 9 | 10 | matrix: 11 | allow_failures: 12 | - rust: nightly 13 | fast_finish: true 14 | 15 | notifications: 16 | email: false 17 | 18 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "synattra" 3 | version = "0.3.0" 4 | authors = ["Simon Chemouil "] 5 | license = "Apache-2.0 OR MIT" 6 | readme = "README.md" 7 | keywords = ["parsing", "macro", "attribute"] 8 | repository = "https://github.com/magnet/synattra" 9 | description = """ 10 | A Syn Attribute Parser Toolkit 11 | """ 12 | categories = ["parsing"] 13 | edition = "2018" 14 | 15 | [dependencies] 16 | syn = {version= "2", features = ["full"] } 17 | proc-macro2 = "1" 18 | auto_enums = "0.8" -------------------------------------------------------------------------------- /LICENSE-APACHE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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IN NO EVENT SHALL THE 16 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 17 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 18 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 19 | SOFTWARE. -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Synattra 2 | [![Build Status](https://travis-ci.org/magnet/synattra.svg?branch=master)](https://travis-ci.org/magnet/synattra) 3 | [![License](https://img.shields.io/badge/license-MIT%2FApache--2.0-blue.svg)]( 4 | https://github.com/magnet/synattra) 5 | [![Cargo](https://img.shields.io/crates/v/synattra.svg)]( 6 | https://crates.io/crates/synattra) 7 | [![Documentation](https://docs.rs/synattra/badge.svg)]( 8 | https://docs.rs/synattra) 9 | [![Rust 1.31+](https://img.shields.io/badge/rust-1.31+-lightgray.svg)]( 10 | https://www.rust-lang.org) 11 | 12 | ## A Syn Attribute Parser Toolkit 13 | 14 | Synattra extends Syn and provides structures to easily parse custom attributes. 15 | 16 | Notably, Synattra provides a `KVOption` type that allows parsing attributes in the form `key = value` where `key` can be any token or custom keyword (including Rust keywords!) and value any type that can be parsed from a `TokenStream`. Synattra was extracted from the [Metered project](https://github.com/magnet/metered-rs) which needed expressing type paths as option values (e.g `path::to::GenericType`), which was not supported by existing attribute parsing systems (neither Syn's own `Meta` parsing facility or alternate crates such as [prom-attire-rs](https://github.com/Nemo157/prom-attire-rs/)). 17 | 18 | Synattra also supports single or multiple values, that can take the shape of `Foo` or `[Foo, Bar]`. 19 | 20 | Finally Synattra provides some extra types, such as `InvokePath` which represents any invocation handle, macro or not (e.g `foo` or `println!`). 21 | 22 | By reusing Syn's design, Synattra parsers are very robust and when they compile, they usually work :-). 23 | 24 | 25 | ## Changelog 26 | 27 | * 0.3.0: 28 | * Updated dependencies to use `syn` 2.0 and `auto_enums` 0.8 29 | * 0.2.0: 30 | * Updated dependencies to use `syn`, `proc-macro2` and `quote` 1.0 31 | 32 | 33 | ## Required Rust version 34 | 35 | Synattra runs on `Rust` stable. 36 | 37 | 38 | ### Design 39 | 40 | Synattra is using Syn's design for attribute parsing. You can see it in use in the [Metered project](https://github.com/magnet/metered-rs). 41 | 42 | 43 | ## License 44 | 45 | Licensed under either of 46 | 47 | * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) 48 | * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) 49 | 50 | at your option. 51 | 52 | ### Contribution 53 | 54 | Unless you explicitly state otherwise, any contribution intentionally 55 | submitted for inclusion in the work by you, as defined in the Apache-2.0 56 | license, shall be dual licensed as above, without any additional terms or 57 | conditions. -------------------------------------------------------------------------------- /src/invoke_path.rs: -------------------------------------------------------------------------------- 1 | use syn::parse::{Parse, ParseStream}; 2 | use syn::Result; 3 | 4 | /// An invocation path that may be `bar::foo` or `bar::foo!` 5 | pub struct InvokePath { 6 | /// The path 7 | pub path: syn::Path, 8 | /// The bang `!` token, if the invocation is a macro invocation. 9 | pub bang: Option, 10 | } 11 | 12 | impl Parse for InvokePath { 13 | fn parse(input: ParseStream) -> Result { 14 | Ok(InvokePath { 15 | path: input.parse()?, 16 | bang: input.parse()?, 17 | }) 18 | } 19 | } 20 | -------------------------------------------------------------------------------- /src/kv_option.rs: -------------------------------------------------------------------------------- 1 | use syn::parse::{Parse, ParseStream}; 2 | use syn::Result; 3 | 4 | /// A Key Value option. 5 | pub struct KVOption { 6 | /// The key 7 | pub key: K, 8 | /// The equal token 9 | pub eq_token: syn::Token![=], 10 | /// The value 11 | pub value: V, 12 | } 13 | 14 | impl KVOption { 15 | /// Look ahead on the stream if the next token corresponds to the key.Default 16 | /// 17 | /// This method does not consume the stream. 18 | pub fn peek(input: ParseStream) -> bool { 19 | K::peek(input.cursor()) 20 | } 21 | } 22 | 23 | impl Parse for KVOption { 24 | fn parse(input: ParseStream) -> Result { 25 | Ok(KVOption { 26 | key: input.parse()?, 27 | eq_token: input.parse()?, 28 | value: input.parse()?, 29 | }) 30 | } 31 | } 32 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | //! # A Syn Attribute Parser Toolkit 2 | //! 3 | //! Synattra extends Syn and provides structures to easily parse custom attributes. 4 | //! 5 | //! Notably, Synattra provides a `KVOption` type that allows parsing attributes in the form `key = value` where `key` can be any token or custom keyword (including Rust keywords!) and value any type that can be parsed from a `TokenStream`. Synattra was extracted from the [Metered project](https://github.com/magnet/metered-rs), please check it for actual usage. 6 | //! 7 | //! Synattra also supports single or multiple values, that can take the shape of `Foo` or `[Foo, Bar]`. 8 | //! 9 | //! Finally Synattra provides some extra types, such as `InvokePath` which represents any invocation handle, macro or not (e.g `foo` or `println!`). 10 | //! 11 | //! By reusing Syn's design, Synattra parsers are very robust and when they compile, they usually work :-). 12 | 13 | #![deny(missing_docs)] 14 | #![deny(warnings)] 15 | 16 | #[macro_use] 17 | extern crate syn; 18 | 19 | mod invoke_path; 20 | mod kv_option; 21 | mod multiple_val; 22 | mod parse_attributes; 23 | mod parse_ext; 24 | 25 | pub use parse_attributes::ParseAttributes; 26 | pub use parse_ext::ParseStreamExt; 27 | 28 | /// Parseable types provided by Synattra 29 | pub mod types { 30 | pub use crate::kv_option::KVOption; 31 | pub use crate::multiple_val::{MultipleVal, MultipleValArray}; 32 | 33 | /// Some extra-types not provided by Syn 34 | pub mod extra { 35 | pub use crate::invoke_path::InvokePath; 36 | } 37 | } 38 | -------------------------------------------------------------------------------- /src/multiple_val.rs: -------------------------------------------------------------------------------- 1 | use crate::parse_ext::*; 2 | use auto_enums::auto_enum; 3 | use syn::parse::{Parse, ParseStream}; 4 | use syn::Result; 5 | /// Single or [MultipleA, MultipleB] values. 6 | pub enum MultipleVal { 7 | /// A Single value 8 | Single(T), 9 | /// Multiple values 10 | Multiple(MultipleValArray), 11 | } 12 | 13 | impl MultipleVal { 14 | /// Returns an iterator over the values 15 | #[auto_enum(Iterator)] 16 | pub fn iter(&self) -> impl Iterator { 17 | match self { 18 | MultipleVal::Single(val) => std::iter::once(val), 19 | MultipleVal::Multiple(arr) => arr.values.iter(), 20 | } 21 | } 22 | } 23 | 24 | impl Parse for MultipleVal { 25 | fn parse(input: ParseStream) -> Result { 26 | Ok(input 27 | .try_parse_as(MultipleVal::Single) 28 | .or_else(|_| input.parse_as(MultipleVal::Multiple))?) 29 | } 30 | } 31 | 32 | /// An array containing several values, [A, B, C] 33 | pub struct MultipleValArray { 34 | /// The bracket tocken '[' and ']' 35 | pub bracket_token: syn::token::Bracket, 36 | /// The comma-separated values 37 | pub values: syn::punctuated::Punctuated, 38 | } 39 | 40 | impl Parse for MultipleValArray { 41 | fn parse(input: ParseStream) -> Result { 42 | let content; 43 | Ok(MultipleValArray { 44 | bracket_token: bracketed!(content in input), 45 | values: content.call(syn::punctuated::Punctuated::parse_terminated)?, 46 | }) 47 | } 48 | } 49 | -------------------------------------------------------------------------------- /src/parse_attributes.rs: -------------------------------------------------------------------------------- 1 | use proc_macro2::TokenStream; 2 | use syn::parse::Parse; 3 | use syn::Result; 4 | 5 | /// A trait to parse attributes 6 | pub trait ParseAttributes { 7 | /// The type of the attributes to parse 8 | type Type: Parse; 9 | 10 | /// Parse the attribute 11 | /// 12 | /// The default implementation should work out of the box 13 | fn parse_attributes(attrs: TokenStream) -> Result { 14 | Ok(syn::parse2(attrs)?) 15 | } 16 | 17 | /// The name of the attribute to parse 18 | /*const*/ 19 | fn fn_attr_name() -> &'static str; 20 | } 21 | -------------------------------------------------------------------------------- /src/parse_ext.rs: -------------------------------------------------------------------------------- 1 | use syn::parse::{Parse, ParseStream}; 2 | use syn::Result; 3 | 4 | /// An extension trait for syn's `ParseStream` 5 | pub trait ParseStreamExt { 6 | /// Try parsing a value, but do not consume the stream if it failed 7 | /// 8 | /// This is a potentially costly method, better used when one knows the parsing will fail early. 9 | fn try_parse(&self) -> Result; 10 | 11 | /// Try parsing a value and apply a function, but do not consume the stream if it failed 12 | /// 13 | /// This method is useful when working with enums. See `parse_as` for an example. 14 | /// 15 | /// This is a potentially costly method, better used when one knows the parsing will fail early. 16 | fn try_parse_as(&self, f: F) -> Result 17 | where 18 | T: Parse, 19 | F: FnOnce(T) -> R, 20 | { 21 | self.try_parse::().map(f) 22 | } 23 | 24 | /// Parse a value and apply a function. 25 | /// 26 | /// This method is useful when working with enums. 27 | /// 28 | /// ``` 29 | /// use syn::Result; 30 | /// use syn::parse::{Parse, ParseStream}; 31 | /// use synattra::types::KVOption; 32 | /// use synattra::ParseStreamExt; 33 | /// 34 | /// mod kw { 35 | /// syn::custom_keyword!(registry); 36 | /// syn::custom_keyword!(registry_expr); 37 | /// } 38 | /// 39 | /// pub type MeteredRegistryOption = KVOption; 40 | /// 41 | /// pub type MeteredRegistryExprOption = KVOption; 42 | /// 43 | /// pub enum MeteredOption { 44 | /// Registry(MeteredRegistryOption), 45 | /// RegistryExpr(MeteredRegistryExprOption), 46 | /// } 47 | /// 48 | /// impl Parse for MeteredOption { 49 | /// fn parse(input: ParseStream) -> Result { 50 | /// if MeteredRegistryOption::peek(input) { 51 | /// Ok(input.parse_as(MeteredOption::Registry)?) 52 | /// } else if MeteredRegistryExprOption::peek(input) { 53 | /// Ok(input.parse_as(MeteredOption::RegistryExpr)?) 54 | /// } else { 55 | /// let err = format!("invalid metered option: {}", input); 56 | /// Err(input.error(err)) 57 | /// } 58 | /// } 59 | /// } 60 | /// ```` 61 | fn parse_as(&self, f: F) -> Result 62 | where 63 | T: Parse, 64 | F: FnOnce(T) -> R; 65 | } 66 | 67 | impl<'a> ParseStreamExt for ParseStream<'a> { 68 | // Advance the stream only if parsing was successful 69 | fn try_parse(&self) -> Result { 70 | let fork = self.fork(); 71 | fork.parse::()?; 72 | self.parse::() 73 | } 74 | 75 | fn parse_as(&self, f: F) -> Result 76 | where 77 | T: Parse, 78 | F: FnOnce(T) -> R, 79 | { 80 | self.parse::().map(f) 81 | } 82 | } 83 | --------------------------------------------------------------------------------