diff options
Diffstat (limited to 'src/libstd')
| -rw-r--r-- | src/libstd/macros.rs | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs index 527bab759b0..a4bcf7fd26c 100644 --- a/src/libstd/macros.rs +++ b/src/libstd/macros.rs @@ -153,9 +153,17 @@ macro_rules! print { /// ``` #[macro_export] #[stable(feature = "rust1", since = "1.0.0")] +#[allow_internal_unstable] macro_rules! println { () => (print!("\n")); - ($($arg:tt)*) => (print!("{}\n", format_args!($($arg)*))); + ($($arg:tt)*) => ({ + #[cfg(not(stage0))] { + ($crate::io::_print(format_args_nl!($($arg)*))); + } + #[cfg(stage0)] { + print!("{}\n", format_args!($($arg)*)) + } + }) } /// Macro for printing to the standard error. @@ -211,7 +219,8 @@ macro_rules! eprint { #[stable(feature = "eprint", since = "1.19.0")] macro_rules! eprintln { () => (eprint!("\n")); - ($($arg:tt)*) => (eprint!("{}\n", format_args!($($arg)*))); + ($fmt:expr) => (eprint!(concat!($fmt, "\n"))); + ($fmt:expr, $($arg:tt)*) => (eprint!(concat!($fmt, "\n"), $($arg)*)); } #[macro_export] @@ -397,6 +406,19 @@ pub mod builtin { ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ }); } + /// Internal version of [`format_args`]. + /// + /// This macro differs from [`format_args`] in that it appends a newline to the format string + /// and nothing more. It is perma-unstable. + /// + /// [`format_args`]: ../std/macro.format_args.html + #[doc(hidden)] + #[unstable(feature = "println_format_args", issue="0")] + #[macro_export] + macro_rules! format_args_nl { + ($fmt:expr) => ({ /* compiler built-in */ }); + ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ }); + } /// Inspect an environment variable at compile time. /// /// This macro will expand to the value of the named environment variable at |