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use std::fmt;
use std::fmt::Display;
use std::str::FromStr;
#[derive(Debug, Eq, PartialEq)]
pub struct Version {
pub major : u32,
pub minor : u32,
pub patch : u32
}
impl Display for Version {
fn fmt( &self, fmtr : &mut fmt::Formatter ) -> fmt::Result {
write!( fmtr, "{}.{}.{}", self.major, self.minor, self.patch )
}
}
impl FromStr for Version {
type Err = String;
fn from_str( s : &str ) -> Result<Version, Self::Err> {
let parts : Vec<Result<u32, &str>> =
s.split( '.' )
.map( | elm | elm.parse::<u32>()
.map_err( |_| elm ) )
.collect();
if parts.len() != 3 {
return
Err( format!( "Invalid version format: expected 3 components, got {}."
, parts.len() ) );
}
for part in &parts {
match part {
&Err( err ) =>
return
Err( format!( "Invalid version format: expected integer, got '{}'."
, err ) ),
_ => {}
}
}
Ok( Version {
major: parts[0].unwrap(),
minor: parts[1].unwrap(),
patch: parts[2].unwrap()
} )
}
}
#[macro_export]
macro_rules! version(
() => ( env!( "CARGO_PKG_VERSION" ) )
);
#[test]
fn does_it_work() {
let ver = FromStr::from_str( &version!() );
assert_eq!( ver, Ok( Version { major: 2, minor: 0, patch: 1 } ) );
let invalids = [ "nope", "1.0", "1.0.x", "1.x.0", "x.0.1", "x.x.x" ];
for invalid in &invalids {
let invv : Result<Version, String> = FromStr::from_str( invalid );
assert!( invv.is_err() );
}
assert_eq!( version!(), "2.0.1" );
}