Polish dump-ast example code
diff --git a/examples/dump-syntax/main.rs b/examples/dump-syntax/main.rs
new file mode 100644
index 0000000..584fe3c
--- /dev/null
+++ b/examples/dump-syntax/main.rs
@@ -0,0 +1,46 @@
+//! Parse a Rust source file into a `syn::File` and print out a debug
+//! representation of the syntax tree.
+//!
+//! Use the following command from this directory to test this program by
+//! running it on its own source code:
+//!
+//! cargo run -- main.rs
+//!
+//! The output will begin with:
+//!
+//! File {
+//! shebang: None,
+//! attrs: [
+//! Attribute {
+//! pound_token: Pound,
+//! style: Inner(
+//! ...
+//! }
+
+extern crate syn;
+
+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");
+ println!("{:#?}", syntax);
+}