projects / rustc.git / blame
| Commit | Line | Data |
|---|---|---|
| 8bb4bdeb XL |
1 | # Identifiers |
| 2 | ||
| 3b2f2976 XL |
3 | > **<sup>Lexer:<sup>** |
| 4 | > IDENTIFIER : | |
| 5 | > XID_start XID_continue<sup>\*</sup> | |
| 6 | > | `_` XID_continue<sup>+</sup> | |
| 7 | ||
| 8bb4bdeb XL |
8 | An identifier is any nonempty Unicode[^non_ascii_idents] string of the following form: |
| 9 | ||
| 10 | Either | |
| 11 | ||
| 7cac9316 XL |
12 | * The first character has property [`XID_start`] |
| 13 | * The remaining characters have property [`XID_continue`] | |
| 8bb4bdeb XL |
14 | |
| 15 | Or | |
| 16 | ||
| 17 | * The first character is `_` | |
| 18 | * The identifier is more than one character, `_` alone is not an identifier | |
| 7cac9316 | 19 | * The remaining characters have property [`XID_continue`] |
| 8bb4bdeb XL |
20 | |
| 21 | that does _not_ occur in the set of [keywords]. | |
| 22 | ||
| 7cac9316 | 23 | > **Note**: [`XID_start`] and [`XID_continue`] as character properties cover the |
| 8bb4bdeb XL |
24 | > character ranges used to form the more familiar C and Java language-family |
| 25 | > identifiers. | |
| 26 | ||
| 7cac9316 XL |
27 | |
| 28 | ||
| 29 | [`XID_start`]: http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AXID_Start%3A%5D&abb=on&g=&i= | |
| 30 | [`XID_continue`]: http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AXID_Continue%3A%5D&abb=on&g=&i= | |
| 3b2f2976 | 31 | [keywords]: keywords.html |
| 8bb4bdeb XL |
32 | [^non_ascii_idents]: Non-ASCII characters in identifiers are currently feature |
| 33 | gated. This is expected to improve soon. |