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Diffstat (limited to '')
-rw-r--r-- | vendor/quick-error/examples/context.rs | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/vendor/quick-error/examples/context.rs b/vendor/quick-error/examples/context.rs new file mode 100644 index 000000000..1d406613e --- /dev/null +++ b/vendor/quick-error/examples/context.rs @@ -0,0 +1,43 @@ +use quick_error::{quick_error, ResultExt}; +use std::env; +use std::fs::File; +use std::io::{self, stderr, Read, Write}; +use std::num::ParseIntError; +use std::path::{Path, PathBuf}; + +quick_error! { + #[derive(Debug)] + pub enum Error { + NoFileName {} + Io(err: io::Error, path: PathBuf) { + display("could not read file {:?}: {}", path, err) + context(path: &'a Path, err: io::Error) + -> (err, path.to_path_buf()) + } + Parse(err: ParseIntError, path: PathBuf) { + display("could not parse file {:?}: {}", path, err) + context(path: &'a Path, err: ParseIntError) + -> (err, path.to_path_buf()) + } + } +} + +fn parse_file() -> Result<u64, Error> { + let fname = env::args().skip(1).next().ok_or(Error::NoFileName)?; + let fname = Path::new(&fname); + let mut file = File::open(fname).context(fname)?; + let mut buf = String::new(); + file.read_to_string(&mut buf).context(fname)?; + Ok(buf.parse().context(fname)?) +} + +fn main() { + match parse_file() { + Ok(val) => { + println!("Read: {}", val); + } + Err(e) => { + writeln!(&mut stderr(), "Error: {}", e).ok(); + } + } +} |