Struct syn::File

source · [−]

pub struct File {
    pub shebang: Option<String>,
    pub attrs: Vec<Attribute>,
    pub items: Vec<Item>,
}

Expand description

A complete file of Rust source code.

This type is available only if Syn is built with the "full" feature.

Example

Parse a Rust source file into a syn::File and print out a debug representation of the syntax tree.

use std::env;
use std::fs::File;
use std::io::Read;
use std::process;

fn main() {
    let mut args = env::args();
    let _ = args.next(); // executable name

    let filename = match (args.next(), args.next()) {
        (Some(filename), None) => filename,
        _ => {
            eprintln!("Usage: dump-syntax path/to/filename.rs");
            process::exit(1);
        }
    };

    let mut file = File::open(&filename).expect("Unable to open file");

    let mut src = String::new();
    file.read_to_string(&mut src).expect("Unable to read file");

    let syntax = syn::parse_file(&src).expect("Unable to parse file");

    // Debug impl is available if Syn is built with "extra-traits" feature.
    println!("{:#?}", syntax);
}

Running with its own source code as input, this program prints output that begins with:

File {
    shebang: None,
    attrs: [],
    items: [
        Use(
            ItemUse {
                attrs: [],
                vis: Inherited,
                use_token: Use,
                leading_colon: None,
                tree: Path(
                    UsePath {
                        ident: Ident(
                            std,
                        ),
                        colon2_token: Colon2,
                        tree: Name(
                            UseName {
                                ident: Ident(
                                    env,
                                ),
                            },
                        ),
                    },
                ),
                semi_token: Semi,
            },
        ),
...