#macro #macro-rules #diagram #edge #macros #syntax #railroad

macro_railroad

A library to generate syntax diagrams for Rust macros

5 releases

new 0.1.4 Mar 19, 2023
0.1.3 Sep 5, 2020
0.1.2 Oct 1, 2019
0.1.1 Sep 28, 2019
0.1.0 Feb 23, 2019

#55 in Procedural macros

36 downloads per month

MIT license

61KB
1.5K SLoC

Build Status Crates.io Version

Live demo (code)

A browser add-on for Firefox, Chrome and Edge

A library to generate syntax ("railroad") diagrams for Rust's macro_rules!().

Diagrams are generated as Scalable Vector Graphics, with layout-details controlled by customizable CSS.

As an example, given the definition of nom's method

macro_rules! method {
    ($name:ident<$a:ty>( $i:ty ) -> $o:ty, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty,$i:ty,$o:ty,$e:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty,$i:ty,$o:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty,$o:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty>( $i:ty ) -> $o:ty, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty,$i:ty,$o:ty,$e:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty,$i:ty,$o:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty,$o:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty>, $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty>( $i:ty ) -> $o:ty, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty,$i:ty,$o:ty,$e:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty,$i:ty,$o:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty,$o:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$a:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty>( $i:ty ) -> $o:ty, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty,$i:ty,$o:ty,$e:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty,$i:ty,$o:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty,$o:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
    (pub $name:ident<$a:ty>, mut $self_:ident, $submac:ident!( $($args:tt)* )) => { ... };
}

... the library generates an SVG which renders (using default CSS) as

Syntax diagram for nom::method


To generate the examples shown here, run

cargo run --example various

which will output some html-files to /examples; Feel free to hack on the demos in /examples/various.rs.

Examples

Dependencies

~0.8–1.2MB
~27K SLoC