diff options
| -rw-r--r-- | src/libcollections/fmt.rs | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/libcollections/fmt.rs b/src/libcollections/fmt.rs index 710a30ff236..d58c26a7213 100644 --- a/src/libcollections/fmt.rs +++ b/src/libcollections/fmt.rs @@ -333,7 +333,7 @@ //! precision := count | '*' //! type := identifier | '' //! count := parameter | integer -//! parameter := integer '$' +//! parameter := argument '$' //! ``` //! //! # Formatting Parameters @@ -403,11 +403,12 @@ //! println!("Hello {:5}!", "x"); //! println!("Hello {:1$}!", "x", 5); //! println!("Hello {1:0$}!", 5, "x"); +//! println!("Hello {:width$}!", "x", width = 5); //! ``` //! //! Referring to an argument with the dollar syntax does not affect the "next -//! argument" counter, so it's usually a good idea to refer to all arguments by -//! their position explicitly. +//! argument" counter, so it's usually a good idea to refer to arguments by +//! position, or use named arguments. //! //! ## Precision //! @@ -426,7 +427,7 @@ //! //! the integer `N` itself is the precision. //! -//! 2. An integer followed by dollar sign `.N$`: +//! 2. An integer or name followed by dollar sign `.N$`: //! //! use format *argument* `N` (which must be a `usize`) as the precision. //! @@ -456,6 +457,10 @@ //! // Hello {next arg (x)} is {arg 2 (0.01) with precision //! // specified in its predecessor (5)} //! println!("Hello {} is {2:.*}", "x", 5, 0.01); +//! +//! // Hello {next arg (x)} is {arg "number" (0.01) with precision specified +//! // in arg "prec" (5)} +//! println!("Hello {} is {number:.prec$}", "x", prec = 5, number = 0.01); //! ``` //! //! All print the same thing: |