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| -rw-r--r-- | src/doc/unstable-book/src/language-features/non-ascii-idents.md | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/src/doc/unstable-book/src/language-features/non-ascii-idents.md b/src/doc/unstable-book/src/language-features/non-ascii-idents.md index d5600c58fd9..a1bb0ce7869 100644 --- a/src/doc/unstable-book/src/language-features/non-ascii-idents.md +++ b/src/doc/unstable-book/src/language-features/non-ascii-idents.md @@ -15,4 +15,34 @@ The `non_ascii_idents` feature adds support for non-ASCII identifiers. const ε: f64 = 0.00001f64; const Π: f64 = 3.14f64; -``` \ No newline at end of file +``` + +## Changes to the language reference + +> **<sup>Lexer:<sup>** +> IDENTIFIER : +> XID_start XID_continue<sup>\*</sup> +> | `_` XID_continue<sup>+</sup> + +An identifier is any nonempty Unicode string of the following form: + +Either + + * The first character has property [`XID_start`] + * The remaining characters have property [`XID_continue`] + +Or + + * The first character is `_` + * The identifier is more than one character, `_` alone is not an identifier + * The remaining characters have property [`XID_continue`] + +that does _not_ occur in the set of [strict keywords]. + +> **Note**: [`XID_start`] and [`XID_continue`] as character properties cover the +> character ranges used to form the more familiar C and Java language-family +> identifiers. + +[`XID_start`]: http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AXID_Start%3A%5D&abb=on&g=&i= +[`XID_continue`]: http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AXID_Continue%3A%5D&abb=on&g=&i= +[strict keywords]: keywords.html#strict-keywords |