rust/src/test/run-pass/concat.rs

pub fn main() {
    assert_eq!(format!(concat!("foo", "bar", "{}"), "baz"), "foobarbaz".to_string());
    assert_eq!(format!(concat!()), "".to_string());
    // check trailing comma is allowed in concat
    assert_eq!(concat!("qux", "quux",).to_string(), "quxquux".to_string());

    assert_eq!(
        concat!(1, 2, 3, 4f32, 4.0, 'a', true),
        "12344.0atrue"
    );

    assert!(match "12344.0atrue" {
        concat!(1, 2, 3, 4f32, 4.0, 'a', true) => true,
        _ => false
    })
}
Implement a concat!() format extension This extension can be used to concatenate string literals at compile time. C has this useful ability when placing string literals lexically next to one another, but this needs to be handled at the syntax extension level to recursively expand macros. The major use case for this is something like: macro_rules! mylog( ($fmt:expr $($arg:tt)) => { error2!(concat!(file!(), ":", line!(), " - ", $fmt) $($arg)); }) Where the mylog macro will automatically prepend the filename/line number to the beginning of every log message. 2013-10-05 23:15:46 -05:00			`pub fn main() {`
std: Rename strbuf operations to string [breaking-change] 2014-05-25 05:17:19 -05:00			`assert_eq!(format!(concat!("foo", "bar", "{}"), "baz"), "foobarbaz".to_string());`
			`assert_eq!(format!(concat!()), "".to_string());`
Allow trailing comma in `concat!` (And in other extensions implemented with `get_exprs_from_tts` function). 2014-06-23 10:51:40 -05:00			`// check trailing comma is allowed in concat`
			`assert_eq!(concat!("qux", "quux",).to_string(), "quxquux".to_string());`
Implement a concat!() format extension This extension can be used to concatenate string literals at compile time. C has this useful ability when placing string literals lexically next to one another, but this needs to be handled at the syntax extension level to recursively expand macros. The major use case for this is something like: macro_rules! mylog( ($fmt:expr $($arg:tt)) => { error2!(concat!(file!(), ":", line!(), " - ", $fmt) $($arg)); }) Where the mylog macro will automatically prepend the filename/line number to the beginning of every log message. 2013-10-05 23:15:46 -05:00
			`assert_eq!(`
Remove integer suffixes where the types in compiled code are identical. 2015-03-03 02:42:26 -06:00			`concat!(1, 2, 3, 4f32, 4.0, 'a', true),`
Implement a concat!() format extension This extension can be used to concatenate string literals at compile time. C has this useful ability when placing string literals lexically next to one another, but this needs to be handled at the syntax extension level to recursively expand macros. The major use case for this is something like: macro_rules! mylog( ($fmt:expr $($arg:tt)) => { error2!(concat!(file!(), ":", line!(), " - ", $fmt) $($arg)); }) Where the mylog macro will automatically prepend the filename/line number to the beginning of every log message. 2013-10-05 23:15:46 -05:00			`"12344.0atrue"`
			`);`
Allow ExprLit expression macros to be used in patterns. 2014-08-30 17:45:11 -05:00
			`assert!(match "12344.0atrue" {`
Remove integer suffixes where the types in compiled code are identical. 2015-03-03 02:42:26 -06:00			`concat!(1, 2, 3, 4f32, 4.0, 'a', true) => true,`
Allow ExprLit expression macros to be used in patterns. 2014-08-30 17:45:11 -05:00			`_ => false`
			`})`
Implement a concat!() format extension This extension can be used to concatenate string literals at compile time. C has this useful ability when placing string literals lexically next to one another, but this needs to be handled at the syntax extension level to recursively expand macros. The major use case for this is something like: macro_rules! mylog( ($fmt:expr $($arg:tt)) => { error2!(concat!(file!(), ":", line!(), " - ", $fmt) $($arg)); }) Where the mylog macro will automatically prepend the filename/line number to the beginning of every log message. 2013-10-05 23:15:46 -05:00			`}`